/* CSS Variables for theming */
:root {
    /* Primary Colors */
    --primary-gradient: linear-gradient(135deg, #7689e0 0%, #764ba2 100%);
    --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --success-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --warning-gradient: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);
    --danger-gradient: linear-gradient(135deg, #fa709a 0%, #fee140 100%);
    
    /* Background Colors */
    --bg-primary: #bde3f9;
    --bg-secondary: #ffffff;
    --bg-card: rgba(255, 255, 255, 0.95);
    --bg-overlay: rgba(0, 0, 0, 0.1);
    
    /* Text Colors */
    --text-primary: #10161f;
    --text-secondary: #4a5568;
    --text-muted: #718096;
    --text-white: #ffffff;
    
    /* Border Colors */
    --border-color: #e2e8f0;
    --border-focus: #667eea;
    
    /* Shadow */
    --shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 20px 40px rgba(0, 0, 0, 0.15);
    --shadow-hover: 0 15px 35px rgba(0, 0, 0, 0.2);
    
    /* Spacing */
    --padding-sm: 0.5rem;
    --padding-md: 1rem;
    --padding-lg: 2rem;
    --padding-xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 30px;
    
    /* Font Sizes */
    --font-xs: 0.75rem;
    --font-sm: 0.875rem;
    --font-md: 1rem;
    --font-lg: 1.125rem;
    --font-xl: 1.25rem;
    --font-2xl: 1.5rem;
    --font-3xl: 2rem;
    --font-4xl: 2.5rem;
    
    /* Transitions */
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.15s ease;
}

/* Dark Mode Variables */
[data-theme="dark"] {
    --primary-gradient: linear-gradient(135deg, #b5bfeb 0%, #764ba2 100%);
    --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    
    --bg-primary: #222b3d;
    --bg-secondary: #2d3748;
    --bg-card: rgba(27, 1, 59, 0.95);
    --bg-overlay: rgba(255, 255, 255, 0.1);
    
    --text-primary: #f7fafc;
    --text-secondary: #e2e8f0;
    --text-muted: #a0aec0;
    
    --border-color: #4a5568;
    --border-focus: #667eea;
    
    --shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 20px 40px rgba(0, 0, 0, 0.4);
    --shadow-hover: 0 15px 35px rgba(0, 0, 0, 0.5);
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: 'Poppins', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    transition: var(--transition);
}

/* Loading Screen */
#loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}

#loading-screen.hidden {
    opacity: 0;
    visibility: hidden;
}

.loader {
    text-align: center;
    color: white;
}

.calculator-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
    animation: bounce 2s infinite;
}

.loading-text {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 2rem;
}

.loading-bar {
    width: 200px;
    height: 4px;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 2px;
    overflow: hidden;
}

.loading-progress {
    height: 100%;
    background: white;
    border-radius: 2px;
    animation: loading 2s ease-in-out infinite;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0);
    }
    40% {
        transform: translateY(-20px);
    }
    60% {
        transform: translateY(-10px);
    }
}

@keyframes loading {
    0% {
        width: 0%;
    }
    50% {
        width: 70%;
    }
    100% {
        width: 100%;
    }
}

/* Theme Toggle */
.theme-toggle {
    position: fixed;
    top: 100px;
    right: 20px;
    z-index: 1000;
}

#theme-switch {
    display: none;
}

.toggle-label {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 60px;
    height: 30px;
    background: var(--bg-secondary);
    border-radius: 15px;
    padding: 5px;
    cursor: pointer;
    box-shadow: var(--shadow);
    transition: var(--transition);
    position: relative;
}

.toggle-label::before {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-gradient);
    transition: var(--transition);
    transform: translateX(0);
}

#theme-switch:checked + .toggle-label::before {
    transform: translateX(30px);
}

.sun-icon, .moon-icon {
    font-size: 0.8rem;
    z-index: 2;
    transition: var(--transition);
}

.sun-icon {
    color: #fbbf24;
}

.moon-icon {
    color: #60a5fa;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    box-shadow: var(--shadow);
    z-index: 999;
    transition: var(--transition);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: var(--font-xl);
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-logo i {
    font-size: 1.5rem;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-menu {
    display: flex;
    gap: 2rem;
    list-style: none;
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    transition: var(--transition);
    position: relative;
}

.nav-link:hover {
    color: var(--text-primary);
    background: var(--bg-overlay);
    transform: translateY(-2px);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 50%;
    width: 0;
    height: 2px;
    background: var(--primary-gradient);
    transition: var(--transition);
    transform: translateX(-50%);
}

.nav-link:hover::after {
    width: 80%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    margin: 3px 0;
    transition: var(--transition);
    border-radius: 2px;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    position: relative;
    overflow: hidden;
    padding: 2rem;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="25" cy="25" r="1" fill="white" opacity="0.1"/><circle cx="75" cy="75" r="1" fill="white" opacity="0.1"/><circle cx="50" cy="10" r="0.5" fill="white" opacity="0.1"/><circle cx="10" cy="60" r="0.5" fill="white" opacity="0.1"/><circle cx="90" cy="40" r="0.5" fill="white" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
    opacity: 0.1;
}

.hero-content {
    text-align: center;
    max-width: 600px;
    z-index: 2;
    position: relative;
}

.hero-title {
    font-size: var(--font-4xl);
    font-weight: 700;
    margin-bottom: 1rem;
    animation: fadeInUp 1s ease;
}

.hero-subtitle {
    font-size: var(--font-xl);
    margin-bottom: 2rem;
    opacity: 0.9;
    animation: fadeInUp 1s ease 0.2s both;
}

.hero-features {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 3rem;
    flex-wrap: wrap;
}

.feature-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(10px);
    animation: fadeInUp 1s ease 0.4s both;
}

.feature-item i {
    font-size: var(--font-lg);
}

.cta-button {
    background: white;
    color: #667eea;
    border: none;
    padding: 1rem 2rem;
    border-radius: var(--radius-lg);
    font-size: var(--font-lg);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    animation: fadeInUp 1s ease 0.6s both;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

.cta-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.3);
}

.hero-animation {
    position: absolute;
    right: 10%;
    top: 50%;
    transform: translateY(-50%);
    opacity: 0.3;
}

.floating-calc {
    font-size: 8rem;
    animation: float 3s ease-in-out infinite;
}

.floating-numbers {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-top: 2rem;
    font-size: 2rem;
    font-weight: 600;
}

.floating-numbers span {
    animation: fadeInScale 2s ease infinite;
}

.floating-numbers span:nth-child(2) { animation-delay: 0.2s; }
.floating-numbers span:nth-child(3) { animation-delay: 0.4s; }
.floating-numbers span:nth-child(4) { animation-delay: 0.6s; }
.floating-numbers span:nth-child(5) { animation-delay: 0.8s; }

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes float {
    0%, 100% {
        transform: translateY(-50px);
    }
    50% {
        transform: translateY(-70px);
    }
}

@keyframes fadeInScale {
    0%, 100% {
        opacity: 0.3;
        transform: scale(1);
    }
    50% {
        opacity: 1;
        transform: scale(1.1);
    }
}

/* Main Content */
.calculators-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 4rem 2rem;
}

.calculator-section {
    margin-bottom: 6rem;
    opacity: 1;
    transform: translateY(0);
    transition: var(--transition);
}

.calculator-section.hidden {
    opacity: 0;
    transform: translateY(50px);
}

.calculator-section.visible {
    opacity: 1;
    transform: translateY(0);
}

.section-header {
    text-align: center;
    margin-bottom: 3rem;
}

.section-header h2 {
    font-size: var(--font-3xl);
    font-weight: 700;
    margin-bottom: 1rem;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section-header p {
    font-size: var(--font-lg);
    color: var(--text-muted);
}

/* Calculator Cards */
.calculator-card {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    padding: var(--padding-xl);
    box-shadow: var(--shadow);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.calculator-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--primary-gradient);
}

.calculator-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

/* Calculator Display */
.calc-display {
    background: #1a202c;
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    margin-bottom: 2rem;
    min-height: 120px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.calc-history {
    color: #a0aec0;
    font-size: var(--font-sm);
    text-align: right;
    min-height: 20px;
}

.calc-result {
    color: white;
    font-size: 2.5rem;
    font-weight: 600;
    text-align: right;
    word-break: break-all;
}

/* Calculator Buttons */
.calc-buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
}

.scientific-buttons {
    grid-template-columns: repeat(5, 1fr);
}

.btn {
    border: none;
    border-radius: var(--radius-md);
    padding: 1rem;
    font-size: var(--font-lg);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    transition: var(--transition);
    transform: translate(-50%, -50%);
}

.btn:active::before {
    width: 300px;
    height: 300px;
}

.btn-number {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-number:hover {
    background: var(--bg-overlay);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.btn-operator {
    background: var(--secondary-gradient);
    color: white;
}

.btn-operator:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.btn-clear {
    background: var(--danger-gradient);
    color: white;
}

.btn-clear:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.btn-equals {
    background: var(--success-gradient);
    color: white;
}

.btn-equals:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.btn-function {
    background: var(--warning-gradient);
    color: white;
    font-size: var(--font-md);
}

.btn-function:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.btn-wide {
    grid-column: span 2;
}

.btn-calculate {
    background: var(--primary-gradient);
    color: white;
    padding: 1rem 2rem;
    border-radius: var(--radius-lg);
    font-size: var(--font-lg);
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    width: 100%;
    margin-top: 1rem;
}

.btn-calculate:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

/* Input Groups */
.input-group {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.input-field {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.input-field label {
    font-weight: 600;
    color: var(--text-secondary);
}

.input-field input,
.input-field select {
    padding: 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: var(--font-md);
    background: var(--bg-secondary);
    color: var(--text-primary);
    transition: var(--transition);
}

.input-field input:focus,
.input-field select:focus {
    outline: none;
    border-color: var(--border-focus);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.input-with-unit {
    display: flex;
    gap: 0.5rem;
}

.input-with-unit input {
    flex: 1;
}

.input-with-unit select {
    min-width: 100px;
}

/* Result Display */
.result-display {
    background: var(--bg-overlay);
    border-radius: var(--radius-lg);
    padding: 2rem;
    margin-top: 2rem;
    text-align: center;
    min-height: 100px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    transition: var(--transition);
}

.result-display.show {
    background: var(--success-gradient);
    color: white;
    transform: scale(1.02);
}

/* BMI Specific Styles */
.bmi-value {
    font-size: var(--font-3xl);
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.bmi-category {
    font-size: var(--font-xl);
    font-weight: 600;
    margin-bottom: 1rem;
}

.bmi-description {
    font-size: var(--font-md);
    opacity: 0.9;
}

.bmi-chart {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 1rem;
    margin-top: 2rem;
}

.chart-item {
    padding: 1rem;
    border-radius: var(--radius-md);
    text-align: center;
    color: white;
    font-weight: 600;
    transition: var(--transition);
}

.chart-item:hover {
    transform: translateY(-3px);
}

.chart-item.underweight {
    background: linear-gradient(135deg, #74b9ff 0%, #0984e3 100%);
}

.chart-item.normal {
    background: linear-gradient(135deg, #00b894 0%, #00a085 100%);
}

.chart-item.overweight {
    background: linear-gradient(135deg, #fdcb6e 0%, #e17055 100%);
}

.chart-item.obese {
    background: linear-gradient(135deg, #fd79a8 0%, #e84393 100%);
}

.chart-item.active {
    transform: scale(1.05);
    box-shadow: var(--shadow-lg);
}

.range {
    display: block;
    font-size: var(--font-lg);
    margin-bottom: 0.5rem;
}

.category {
    display: block;
    font-size: var(--font-sm);
    opacity: 0.9;
}

/* Age Calculator Styles */
.age-main {
    font-size: var(--font-3xl);
    font-weight: 700;
    margin-bottom: 1rem;
}

.age-details {
    font-size: var(--font-lg);
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

.age-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
    margin-top: 1rem;
}

.age-stat {
    background: var(--bg-secondary);
    padding: 1rem;
    border-radius: var(--radius-md);
    text-align: center;
}

.age-stat-value {
    font-size: var(--font-xl);
    font-weight: 700;
    color: var(--text-primary);
}

.age-stat-label {
    font-size: var(--font-sm);
    color: var(--text-muted);
    margin-top: 0.5rem;
}

.age-milestones {
    margin-top: 2rem;
    padding: 1.5rem;
    background: var(--bg-overlay);
    border-radius: var(--radius-lg);
}

.milestone {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.milestone:last-child {
    border-bottom: none;
}

.milestone-name {
    font-weight: 600;
}

.milestone-date {
    color: var(--text-muted);
    font-size: var(--font-sm);
}

/* Loan Calculator Styles */
.loan-summary {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.summary-item {
    background: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.summary-item:hover {
    transform: translateY(-3px);
}

.summary-item .label {
    display: block;
    font-size: var(--font-sm);
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}

.summary-item .value {
    display: block;
    font-size: var(--font-2xl);
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.loan-chart {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow);
}

#loan-chart-canvas {
    max-width: 100%;
    height: 300px;
}

/* Percentage Calculator Styles */
.percentage-tabs,
.converter-tabs {
    display: flex;
    background: var(--bg-overlay);
    border-radius: var(--radius-lg);
    padding: 0.5rem;
    margin-bottom: 2rem;
    overflow-x: auto;
}

.tab-btn {
    flex: 1;
    padding: 1rem;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-weight: 600;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

.tab-btn.active {
    background: var(--primary-gradient);
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.tab-btn:not(.active):hover {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.percentage-content,
.converter-content {
    position: relative;
}

.tab-content {
    display: none;
    animation: fadeIn 0.3s ease;
}

.tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Unit Converter Styles */
.converter-row {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 2rem;
    align-items: end;
}

.converter-arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 50px;
    height: 50px;
    background: var(--primary-gradient);
    border-radius: 50%;
    color: white;
    font-size: var(--font-xl);
    cursor: pointer;
    transition: var(--transition);
}

.converter-arrow:hover {
    transform: scale(1.1) rotate(180deg);
}

/* Footer */
.footer {
    background: #2d3748;
    color: white;
    padding: 3rem 0 1rem;
    margin-top: 4rem;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.footer-section h3 {
    font-size: var(--font-xl);
    font-weight: 600;
    margin-bottom: 1rem;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: var(--font-xl);
    font-weight: 700;
    margin-bottom: 1rem;
}

.footer-section p {
    color: #a0aec0;
    margin-bottom: 1rem;
    line-height: 1.6;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section ul li a {
    color: #a0aec0;
    text-decoration: none;
    transition: var(--transition);
}

.footer-section ul li a:hover {
    color: white;
    padding-left: 0.5rem;
}

.social-links {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--primary-gradient);
    color: white;
    border-radius: 50%;
    text-decoration: none;
    transition: var(--transition);
}

.social-links a:hover {
    transform: translateY(-3px) scale(1.1);
    box-shadow: var(--shadow);
}

.footer-bottom {
    border-top: 1px solid #4a5568;
    margin-top: 2rem;
    padding-top: 1rem;
    text-align: center;
    color: #a0aec0;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background: var(--bg-card);
        width: 100%;
        text-align: center;
        transition: var(--transition);
        box-shadow: var(--shadow);
        backdrop-filter: blur(20px);
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.active .bar:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .nav-toggle.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }

    .hero-title {
        font-size: var(--font-3xl);
    }

    .hero-subtitle {
        font-size: var(--font-lg);
    }

    .hero-features {
        flex-direction: column;
        align-items: center;
    }

    .hero-animation {
        display: none;
    }

    .calc-buttons {
        grid-template-columns: repeat(4, 1fr);
        gap: 0.5rem;
    }

    .scientific-buttons {
        grid-template-columns: repeat(4, 1fr);
    }

    .btn {
        padding: 0.8rem;
        font-size: var(--font-md);
    }

    .calc-result {
        font-size: 2rem;
    }

    .input-group {
        grid-template-columns: 1fr;
    }

    .converter-row {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .converter-arrow {
        transform: rotate(90deg);
        margin: 0 auto;
    }

    .percentage-tabs,
    .converter-tabs {
        flex-wrap: wrap;
    }

    .theme-toggle {
        top: 80px;
        right: 10px;
    }
}

@media (max-width: 480px) {
    .calculators-container {
        padding: 2rem 1rem;
    }

    .calculator-card {
        padding: 1.5rem;
    }

    .section-header h2 {
        font-size: var(--font-2xl);
    }

    .hero {
        padding: 1rem;
    }

    .nav-container {
        padding: 0 1rem;
    }

    .footer-content {
        padding: 0 1rem;
        grid-template-columns: 1fr;
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Print Styles */
@media print {
    .navbar,
    .theme-toggle,
    .footer,
    #loading-screen {
        display: none !important;
    }

    .calculator-section {
        break-inside: avoid;
        page-break-inside: avoid;
    }

    .hero {
        min-height: 0;
        padding: 2rem 0;
    }
}









/* ========================================
   TIP CALCULATOR STYLES
======================================== */

#tip-calculator .calculator-card,
#investment-calculator .calculator-card,
#currency-converter .calculator-card {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    padding: var(--padding-xl);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
    backdrop-filter: blur(20px);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    max-width: 100%;
    width: 100%;
    box-sizing: border-box;
}

#tip-calculator .calculator-card::before,
#investment-calculator .calculator-card::before,
#currency-converter .calculator-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--primary-gradient);
}

#tip-calculator .input-group {
    display: grid;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

#tip-calculator .input-field {
    position: relative;
}

#tip-calculator .input-field label {
    display: block;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    font-size: var(--font-sm);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

#tip-calculator input[type="number"],
#tip-calculator input[type="range"] {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: var(--font-base);
    transition: var(--transition);
}

#tip-calculator input[type="number"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

/* Range input styling for tip calculator */
#tip-calculator input[type="range"] {
    height: 8px;
    background: var(--bg-overlay);
    border: none;
    border-radius: var(--radius-full);
    outline: none;
    padding: 0;
    margin: 0.5rem 0;
}

#tip-calculator input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 24px;
    height: 24px;
    background: var(--primary-gradient);
    border-radius: 50%;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow);
}

#tip-calculator input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-lg);
}

#tip-calculator input[type="range"]::-moz-range-thumb {
    width: 24px;
    height: 24px;
    background: var(--primary-gradient);
    border-radius: 50%;
    cursor: pointer;
    border: none;
    transition: var(--transition);
    box-shadow: var(--shadow);
}

#tip-display {
    font-weight: 700;
    color: var(--primary-color);
    margin-left: 1rem;
    font-size: var(--font-lg);
    text-shadow: 0 2px 4px rgba(102, 126, 234, 0.3);
}

.tip-calculator-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-top: 2rem;
}

.tip-breakdown, .per-person {
    background: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.tip-breakdown::before, .per-person::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--primary-gradient);
}

.tip-breakdown h3, .per-person h3 {
    margin: 0 0 1rem 0;
    color: var(--text-primary);
    font-weight: 700;
    font-size: var(--font-lg);
}

.breakdown-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.breakdown-item:last-child {
    border-bottom: none;
}

.breakdown-item.total {
    font-weight: 800;
    font-size: var(--font-xl);
    margin-top: 0.5rem;
    padding-top: 0.75rem;
    border-top: 2px solid var(--primary-color);
    color: var(--primary-color);
}

.per-person-amount {
    font-size: var(--font-3xl);
    font-weight: 800;
    text-align: center;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-top: 0.75rem;
    text-shadow: 0 4px 8px rgba(102, 126, 234, 0.3);
}

/* ========================================
   INVESTMENT CALCULATOR STYLES
======================================== */

#investment-calculator .input-group {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

#investment-calculator .input-field {
    position: relative;
}

#investment-calculator .input-field label {
    display: block;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    font-size: var(--font-sm);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

#investment-calculator input[type="number"] {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: var(--font-base);
    transition: var(--transition);
}

#investment-calculator input[type="number"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
    transform: translateY(-2px);
}

.investment-summary {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.investment-summary .summary-item {
    background: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.investment-summary .summary-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--primary-gradient);
}

.investment-summary .summary-item .label {
    display: block;
    font-size: var(--font-sm);
    color: var(--text-secondary);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 0.5rem;
}

.investment-summary .summary-item .value {
    display: block;
    font-size: var(--font-2xl);
    font-weight: 800;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

#investmentChart {
    width: 100%;
    max-height: 300px;
    margin-top: 1.5rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    background: var(--bg-secondary);
}

/* ========================================
   CURRENCY CONVERTER STYLES
======================================== */

.converter-row {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 1.5rem;
    align-items: end;
    margin-bottom: 1.5rem;
}

#currency-converter .input-field {
    position: relative;
}

#currency-converter .input-field label {
    display: block;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    font-size: var(--font-sm);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.input-with-unit {
    display: flex;
    gap: 0.5rem;
    align-items: stretch;
}

.input-with-unit input {
    flex: 1;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md) 0 0 var(--radius-md);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: var(--font-base);
    transition: var(--transition);
}

.input-with-unit select {
    min-width: 140px;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-left: none;
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-size: var(--font-sm);
    cursor: pointer;
    transition: var(--transition);
}

.input-with-unit input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
    transform: translateY(-2px);
}

.input-with-unit select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.converter-arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 50px;
    height: 50px;
    background: var(--primary-gradient);
    border-radius: 50%;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow);
    color: white;
}

.converter-arrow:hover {
    transform: scale(1.1) rotate(180deg);
    box-shadow: var(--shadow-lg);
}

.converter-arrow i {
    font-size: var(--font-lg);
}

.exchange-rate-display {
    text-align: center;
    margin-top: 1rem;
    padding: 0.75rem 1rem;
    background: var(--bg-overlay);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    font-weight: 600;
    color: var(--text-secondary);
}

/* ========================================
   RESPONSIVE DESIGN FOR LAST 3 CALCULATORS
======================================== */

@media (max-width: 1200px) {
    #tip-calculator .calculator-card,
    #investment-calculator .calculator-card,
    #currency-converter .calculator-card {
        padding: 2rem;
    }
    
    .tip-calculator-grid {
        gap: 1.5rem;
    }
    
    .converter-row {
        gap: 1rem;
    }
}

@media (max-width: 992px) {
    #investment-calculator .input-group {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    }
    
    .investment-summary {
        grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    }
    
    .tip-calculator-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
}

@media (max-width: 768px) {
    #tip-calculator .calculator-card,
    #investment-calculator .calculator-card,
    #currency-converter .calculator-card {
        padding: 1.5rem;
        margin: 0 1rem;
    }
    
    .tip-calculator-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .converter-row {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .converter-arrow {
        width: 50px;
        height: 50px;
        align-self: center;
        margin: 0.5rem auto;
    }
    
    .converter-arrow:hover {
        transform: scale(1.05) rotate(90deg);
    }
    
    #investment-calculator .input-group {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .investment-summary {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    #tip-calculator .input-group,
    #investment-calculator .input-group {
        gap: 1rem;
    }
    
    .input-with-unit {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .input-with-unit input {
        border-radius: var(--radius-md);
    }
    
    .input-with-unit select {
        border-radius: var(--radius-md);
        border: 2px solid var(--border-color);
        min-width: auto;
    }
}

@media (max-width: 640px) {
    #tip-calculator .calculator-card,
    #investment-calculator .calculator-card,
    #currency-converter .calculator-card {
        padding: 1rem;
        margin: 0 0.5rem;
    }
    
    .tip-breakdown, .per-person {
        padding: 1rem;
    }
    
    .per-person-amount {
        font-size: var(--font-2xl);
    }
    
    .breakdown-item {
        padding: 0.4rem 0;
        font-size: var(--font-sm);
    }
    
    #investmentChart {
        max-height: 250px;
        margin-top: 1rem;
    }
    
    .investment-summary .summary-item {
        padding: 1rem;
    }
    
    .investment-summary .summary-item .value {
        font-size: var(--font-xl);
    }
}

@media (max-width: 480px) {
    #tip-calculator .calculator-card,
    #investment-calculator .calculator-card,
    #currency-converter .calculator-card {
        padding: 1rem;
        margin: 0;
        border-radius: var(--radius-lg);
    }
    
    .per-person-amount {
        font-size: var(--font-xl);
    }
    
    .investment-summary .summary-item .value {
        font-size: var(--font-lg);
    }
    
    .tip-calculator-grid {
        gap: 1rem;
    }
    
    .tip-breakdown h3, .per-person h3 {
        font-size: var(--font-md);
        margin-bottom: 0.75rem;
    }
    
    #tip-calculator input[type="range"]::-webkit-slider-thumb,
    #tip-calculator input[type="range"]::-moz-range-thumb {
        width: 20px;
        height: 20px;
    }
    
    .converter-arrow {
        width: 40px;
        height: 40px;
    }
    
    .converter-arrow i {
        font-size: var(--font-md);
    }
    
    .exchange-rate-display {
        padding: 0.5rem;
        font-size: var(--font-sm);
    }
}

@media (max-width: 360px) {
    #tip-calculator .calculator-card,
    #investment-calculator .calculator-card,
    #currency-converter .calculator-card {
        padding: 0.75rem;
        margin: 0;
    }
    
    .tip-breakdown, .per-person {
        padding: 0.75rem;
    }
    
    .per-person-amount {
        font-size: var(--font-lg);
    }
    
    .breakdown-item {
        font-size: var(--font-xs);
        padding: 0.3rem 0;
    }
    
    #investmentChart {
        max-height: 200px;
    }
    
    .investment-summary .summary-item {
        padding: 0.75rem;
    }
    
    .investment-summary .summary-item .value {
        font-size: var(--font-md);
    }
    
    .converter-arrow {
        width: 35px;
        height: 35px;
    }
}

/* ========================================
   CALCULATOR ANIMATIONS & EFFECTS
======================================== */

/* Smooth result display animations */
#tip-calculator .result-display,
#investment-calculator .result-display,
#currency-converter .result-display {
    animation: slideInUp 0.6s ease-out;
}

@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Input focus animations */
#tip-calculator input:focus,
#investment-calculator input:focus,
#currency-converter input:focus,
#currency-converter select:focus {
    animation: inputFocus 0.3s ease-out;
}

@keyframes inputFocus {
    0% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.02);
    }
    100% {
        transform: scale(1);
    }
}

/* Calculator card hover effects */
#tip-calculator .calculator-card:hover,
#investment-calculator .calculator-card:hover,
#currency-converter .calculator-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

/* Button pulse animation for calculate buttons */
#investment-calculator .btn-calculate {
    position: relative;
    overflow: hidden;
}

#investment-calculator .btn-calculate::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: var(--transition);
}

#investment-calculator .btn-calculate:hover::before {
    width: 300px;
    height: 300px;
}

/* Loading state for currency converter */
.exchange-rate-display.loading {
    position: relative;
    color: transparent;
}

.exchange-rate-display.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    margin: -10px 0 0 -10px;
    border: 2px solid var(--primary-color);
    border-top: 2px solid transparent;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Enhanced hover states */
.tip-breakdown:hover,
.per-person:hover,
.investment-summary .summary-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

/* Range slider track animation */
#tip-calculator input[type="range"]::-webkit-slider-track {
    background: linear-gradient(to right, 
        var(--primary-color) 0%, 
        var(--primary-color) var(--range-percent, 50%), 
        var(--bg-overlay) var(--range-percent, 50%), 
        var(--bg-overlay) 100%);
}

/* Success state animations */
.result-display.success {
    animation: successPulse 0.8s ease-out;
}

@keyframes successPulse {
    0% {
        transform: scale(1);
        box-shadow: 0 0 0 0 rgba(102, 126, 234, 0.4);
    }
    50% {
        transform: scale(1.02);
        box-shadow: 0 0 0 10px rgba(102, 126, 234, 0.1);
    }
    100% {
        transform: scale(1);
        box-shadow: 0 0 0 0 rgba(102, 126, 234, 0);
    }
}

/* Container adjustments for better screen fitting */
@media (max-width: 1400px) {
    .calculators-container {
        max-width: 95%;
        padding: 3rem 1.5rem;
    }
}

@media (max-width: 1024px) {
    .calculators-container {
        max-width: 100%;
        padding: 2.5rem 1rem;
    }
    
    .calculator-section {
        margin-bottom: 4rem;
    }
}

/* Viewport height adjustments */
@media (max-height: 600px) {
    #investmentChart {
        max-height: 200px;
    }
    
    .tip-calculator-grid {
        gap: 1rem;
    }
    
    .tip-breakdown, .per-person {
        padding: 1rem;
    }
}

/* Ultra-wide screen adjustments */
@media (min-width: 1800px) {
    .calculators-container {
        max-width: 1400px;
    }
    
    #tip-calculator .calculator-card,
    #investment-calculator .calculator-card,
    #currency-converter .calculator-card {
        max-width: 1200px;
        margin: 0 auto;
    }
}

.history-panel {
    position: fixed;
    top: 80px;
    right: -400px;
    width: 380px;
    height: calc(100vh - 100px);
    background: var(--bg-card);
    box-shadow: var(--shadow-lg);
    border-radius: var(--radius-lg) 0 0 var(--radius-lg);
    transition: var(--transition);
    z-index: 1000;
    overflow-y: auto;
}

.history-panel.show {
    right: 0;
}

.history-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.history-header h3 {
    margin: 0;
    color: var(--text-primary);
}

.history-list {
    padding: 1rem;
}

.history-item {
    padding: 1rem;
    background: var(--bg-overlay);
    border-radius: var(--radius-md);
    margin-bottom: 0.5rem;
    cursor: pointer;
    transition: var(--transition);
}

.history-item:hover {
    background: var(--primary-gradient);
    color: white;
    transform: translateX(5px);
}

.voice-calculator {
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 1000;
}

.voice-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem 1.5rem;
    background: var(--primary-gradient);
    color: white;
    border: none;
    border-radius: var(--radius-lg);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow);
}

.voice-btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
}

.voice-status {
    text-align: center;
    margin-top: 0.5rem;
    font-size: var(--font-sm);
    color: var(--text-muted);
}

.voice-result {
    display: none;
    margin-top: 1rem;
    padding: 1rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    border: 2px solid var(--primary-color);
}

.voice-calculation {
    text-align: center;
}

.voice-expression {
    font-size: var(--font-lg);
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.voice-answer {
    font-size: var(--font-2xl);
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.voice-btn.listening {
    background: var(--danger-gradient);
    animation: pulse 1.5s infinite;
}

@keyframes pulse {
    0% {
        box-shadow: 0 0 0 0 rgba(255, 0, 0, 0.7);
    }
    70% {
        box-shadow: 0 0 0 10px rgba(255, 0, 0, 0);
    }
    100% {
        box-shadow: 0 0 0 0 rgba(255, 0, 0, 0);
    }
}

/* Notification System */
.notification-container {
    position: fixed;
    top: 100px;
    right: 20px;
    z-index: 9999;
    pointer-events: none;
}

.notification {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    margin-bottom: 1rem;
    opacity: 0;
    transform: translateX(100%);
    transition: var(--transition);
    pointer-events: auto;
    min-width: 300px;
    max-width: 400px;
}

.notification.show {
    opacity: 1;
    transform: translateX(0);
}

.notification-content {
    display: flex;
    align-items: center;
    padding: 1rem;
    gap: 1rem;
}

.notification-icon {
    font-size: var(--font-lg);
}

.notification-message {
    flex: 1;
    color: var(--text-primary);
}

.notification-close {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-muted);
    padding: 0.25rem;
    border-radius: 50%;
    transition: var(--transition);
}

.notification-close:hover {
    background: var(--bg-overlay);
    color: var(--text-primary);
}

.notification-success {
    border-left: 4px solid #00b894;
}

.notification-success .notification-icon {
    color: #00b894;
}

.notification-error {
    border-left: 4px solid #e17055;
}

.notification-error .notification-icon {
    color: #e17055;
}

.notification-warning {
    border-left: 4px solid #fdcb6e;
}

.notification-warning .notification-icon {
    color: #fdcb6e;
}

.notification-info {
    border-left: 4px solid #74b9ff;
}

.notification-info .notification-icon {
    color: #74b9ff;
}

/* Responsive fixes for new features */
@media (max-width: 768px) {
    .tip-calculator-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .investment-summary {
        grid-template-columns: 1fr;
    }
    
    .history-panel {
        width: 100%;
        right: -100%;
        top: 70px;
        height: calc(100vh - 70px);
        border-radius: 0;
    }
    
    .voice-calculator {
        bottom: 20px;
        right: 20px;
    }
    
    .voice-btn {
        padding: 0.8rem 1rem;
        font-size: var(--font-sm);
    }
    
    .voice-result {
        margin-top: 0.5rem;
        padding: 0.75rem;
    }
    
    .voice-expression {
        font-size: var(--font-md);
    }
    
    .voice-answer {
        font-size: var(--font-xl);
    }
    
    .notification {
        min-width: 280px;
        max-width: calc(100vw - 40px);
    }
}