/**
 * Flashcard Generator - Main Stylesheet
 * Mobile-first responsive design
 * Color scheme: Deep Blue (#1E3A8A), Teal (#0F766E), Amber (#F59E0B)
 */

/* ===== CSS Variables ===== */
:root {
    --color-primary: #1E3A8A;
    --color-secondary: #0F766E;
    --color-accent: #F59E0B;
    --color-bg-main: #F8FAFC;
    --color-bg-card: #FFFFFF;
    --color-text-primary: #0F172A;
    --color-text-secondary: #475569;
    --color-border: #E2E8F0;

    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);

    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;

    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
    font-family: var(--font-family);
    color: var(--color-text-primary);
    background-color: var(--color-bg-main);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--color-secondary);
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 0.5em;
    color: var(--color-text-primary);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: 1em;
}

.lead {
    font-size: 1.25rem;
    font-weight: 400;
    color: var(--color-text-secondary);
}

/* ===== Layout ===== */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.section {
    padding: 4rem 0;
}

.bg-light {
    background-color: var(--color-bg-card);
}

/* ===== Header & Navigation ===== */
.header {
    background: var(--color-bg-card);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
}

.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem;
    gap: 2rem;
}

.nav-brand .logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--color-primary);
}

.nav-brand .logo:hover {
    opacity: 0.8;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-link {
    font-weight: 500;
    color: var(--color-text-secondary);
    transition: var(--transition);
}

.nav-link:hover {
    color: var(--color-primary);
}

.user-menu {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-name {
    font-weight: 600;
    color: var(--color-text-primary);
    font-size: 0.9375rem;
}

.user-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    color: white;
    border: none;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.user-avatar:hover {
    transform: scale(1.05);
    box-shadow: var(--shadow-md);
}

.dropdown-menu {
    position: absolute;
    top: calc(100% + 0.5rem);
    right: 0;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    min-width: 200px;
    padding: 0.5rem 0;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: var(--transition);
}

.dropdown-menu.active {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-menu a {
    display: block;
    padding: 0.75rem 1.25rem;
    color: var(--color-text-primary);
    transition: var(--transition);
}

.dropdown-menu a:hover {
    background: var(--color-bg-main);
    color: var(--color-primary);
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 0.25rem;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.mobile-menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--color-text-primary);
    transition: var(--transition);
}

/* ===== Hero Section ===== */
.hero {
    padding: 4rem 0 6rem;
    background: linear-gradient(135deg, #f8fafc 0%, #e0f2fe 100%);
}

.hero-content {
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
}

.hero-title {
    font-size: clamp(2rem, 5vw, 3.5rem);
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-title .accent {
    display: block;
    font-size: 0.6em;
    font-weight: 600;
    margin-top: 0.5rem;
    background: linear-gradient(135deg, var(--color-secondary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-text-secondary);
    margin-bottom: 2.5rem;
    line-height: 1.6;
}

/* ===== Trust Indicators ===== */
.trust-indicators {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 3rem;
}

.trust-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--color-text-secondary);
    font-size: 0.95rem;
    font-weight: 500;
}

.trust-item .icon {
    width: 20px;
    height: 20px;
    color: var(--color-accent);
}

/* ===== Generator Card ===== */
.generator-card {
    background: var(--color-bg-card);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    padding: 2rem;
    margin-top: 2rem;
}

.generator-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 2rem;
    border-bottom: 2px solid var(--color-border);
}

.tab-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem 1.5rem;
    background: none;
    border: none;
    border-bottom: 3px solid transparent;
    color: var(--color-text-secondary);
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    margin-bottom: -2px;
}

.tab-btn:hover {
    color: var(--color-primary);
    background: var(--color-bg-main);
}

.tab-btn.active {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
}

.tab-icon {
    width: 20px;
    height: 20px;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
    animation: fadeIn 0.3s ease-in;
}

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

/* ===== Form Inputs ===== */
.input-textarea,
.input-url,
.input-text,
.input-select,
.input-number {
    width: 100%;
    padding: 1rem;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-family: var(--font-family);
    font-size: 1rem;
    color: var(--color-text-primary);
    transition: var(--transition);
    background: var(--color-bg-card);
}

.input-textarea {
    resize: vertical;
    min-height: 200px;
    line-height: 1.6;
}

.input-textarea:focus,
.input-url:focus,
.input-text:focus,
.input-select:focus,
.input-number:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(30, 58, 138, 0.1);
}

.input-textarea::placeholder {
    color: var(--color-text-secondary);
    opacity: 0.7;
}

.input-help {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 0.75rem;
    font-size: 0.875rem;
    color: var(--color-text-secondary);
}

.icon-sm {
    width: 16px;
    height: 16px;
}

/* ===== Input Suggestions ===== */
.input-suggestions {
    margin-top: 1.5rem;
}

.suggestions-label {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    margin-bottom: 0.75rem;
    font-weight: 500;
}

.suggestion-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.chip {
    padding: 0.5rem 1rem;
    background: var(--color-bg-main);
    border: 1px solid var(--color-border);
    border-radius: 999px;
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
}

.chip:hover {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* ===== File Upload ===== */
.upload-area {
    border: 2px dashed var(--color-border);
    border-radius: var(--radius-lg);
    padding: 3rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
}

.upload-area:hover {
    border-color: var(--color-primary);
    background: rgba(30, 58, 138, 0.02);
}

.upload-icon {
    width: 48px;
    height: 48px;
    margin: 0 auto 1rem;
    color: var(--color-secondary);
}

.upload-area h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--color-text-primary);
}

.upload-area p {
    color: var(--color-text-secondary);
    margin-bottom: 0.25rem;
}

.upload-hint {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    opacity: 0.8;
}

.file-preview {
    margin-top: 1rem;
}

.file-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background: var(--color-bg-main);
    border-radius: var(--radius-md);
}

.file-icon {
    width: 40px;
    height: 40px;
    color: var(--color-primary);
}

.file-name {
    font-weight: 600;
    color: var(--color-text-primary);
}

.file-size {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
}

/* ===== Advanced Options ===== */
.advanced-options {
    margin-top: 2rem;
    padding-top: 2rem;
    border-top: 1px solid var(--color-border);
}

.options-toggle {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    padding: 0.75rem 1rem;
    background: var(--color-bg-main);
    border: none;
    border-radius: var(--radius-md);
    font-weight: 600;
    color: var(--color-text-primary);
    cursor: pointer;
    transition: var(--transition);
}

.options-toggle:hover {
    background: var(--color-border);
}

.chevron {
    width: 20px;
    height: 20px;
    transition: transform 0.3s;
}

.options-toggle.active .chevron {
    transform: rotate(180deg);
}

.options-content {
    margin-top: 1.5rem;
    padding: 1.5rem;
    background: var(--color-bg-main);
    border-radius: var(--radius-md);
    display: grid;
    gap: 1.5rem;
}

.option-group label {
    display: block;
    font-weight: 600;
    color: var(--color-text-primary);
    margin-bottom: 0.5rem;
}

.option-hint {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    margin-top: 0.5rem;
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-family);
    font-size: 1rem;
    text-decoration: none;
    white-space: nowrap;
}

.btn-primary {
    background: var(--color-primary);
    color: white;
}

.btn-primary:hover {
    background: #1e40af;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    color: white;
}

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

.btn-secondary:hover {
    background: #0f766e;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    color: white;
}

.btn-outline {
    background: transparent;
    color: var(--color-text-primary);
    border: 2px solid var(--color-border);
}

.btn-outline:hover {
    background: var(--color-bg-main);
    border-color: var(--color-primary);
    color: var(--color-primary);
}

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-generate {
    width: 100%;
    margin-top: 2rem;
    padding: 1.25rem;
    font-size: 1.125rem;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
}

.btn-generate:hover {
    background: linear-gradient(135deg, #1e40af, #0f766e);
}

/* SVG icons inside buttons */
.btn svg {
    width: 20px;
    height: 20px;
    margin-right: 0.5rem;
    flex-shrink: 0;
}

.btn-generate svg {
    width: 22px;
    height: 22px;
}

.btn-icon {
    background: none;
    border: none;
    padding: 0.5rem;
    cursor: pointer;
    color: var(--color-text-secondary);
    transition: var(--transition);
}

.btn-icon:hover {
    color: var(--color-primary);
}

.btn-icon svg {
    width: 20px;
    height: 20px;
}

/* ===== Progress Indicator ===== */
.progress-indicator {
    text-align: center;
    padding: 2rem;
}

.spinner {
    width: 48px;
    height: 48px;
    margin: 0 auto 1rem;
    border: 4px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.progress-text {
    font-weight: 600;
    color: var(--color-text-primary);
    margin-bottom: 1rem;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--color-border);
    border-radius: 999px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
    border-radius: 999px;
    transition: width 0.3s ease;
    animation: progressPulse 1.5s ease-in-out infinite;
}

@keyframes progressPulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

/* ===== Features Section ===== */
.section-title {
    text-align: center;
    font-size: clamp(2rem, 4vw, 2.5rem);
    margin-bottom: 1rem;
}

.section-subtitle {
    text-align: center;
    font-size: 1.125rem;
    color: var(--color-text-secondary);
    max-width: 600px;
    margin: 0 auto 3rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.feature-card {
    padding: 2rem;
    background: var(--color-bg-card);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

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

.feature-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.feature-icon svg {
    width: 28px;
    height: 28px;
    color: white;
}

.feature-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
}

.feature-card p {
    color: var(--color-text-secondary);
    line-height: 1.6;
}

/* ===== Steps Section ===== */
.steps {
    display: grid;
    gap: 3rem;
    margin-top: 3rem;
}

.step {
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 2rem;
    align-items: center;
}

.step-number {
    width: 64px;
    height: 64px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    color: white;
    font-size: 2rem;
    font-weight: 700;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.step-content h3 {
    font-size: 1.5rem;
    margin-bottom: 0.75rem;
}

.step-content p {
    color: var(--color-text-secondary);
    line-height: 1.6;
}

.step-visual {
    width: 200px;
    height: 150px;
}

/* ===== Benefits Section ===== */
.benefits-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: start;
}

.benefit-items {
    display: grid;
    gap: 2rem;
    margin: 2rem 0;
}

.benefit-item {
    display: flex;
    gap: 1rem;
}

.benefit-icon {
    width: 24px;
    height: 24px;
    color: var(--color-accent);
    flex-shrink: 0;
}

.benefit-item h4 {
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
}

.benefit-item p {
    color: var(--color-text-secondary);
    line-height: 1.6;
}

.benefits-stats {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

.stat-card {
    padding: 2rem;
    background: var(--color-bg-card);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    text-align: center;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-weight: 600;
    color: var(--color-text-primary);
    margin: 0.5rem 0;
}

.stat-card p {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
}

/* ===== FAQ Section ===== */
.faq-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.faq-item {
    padding: 2rem;
    background: var(--color-bg-card);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
}

.faq-question {
    font-size: 1.125rem;
    color: var(--color-primary);
    margin-bottom: 1rem;
}

.faq-answer {
    color: var(--color-text-secondary);
    line-height: 1.7;
}

/* ===== Science Section ===== */
.science-section {
    background: linear-gradient(180deg, var(--color-bg-main) 0%, #f0f9ff 100%);
}

.science-section .section-header {
    text-align: center;
    max-width: 800px;
    margin: 0 auto 3rem;
}

.science-section h2 {
    color: var(--color-primary);
    margin-bottom: 1rem;
}

.science-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.science-card {
    background: white;
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    border: 2px solid transparent;
}

.science-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary);
}

.science-icon {
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.science-icon svg {
    width: 32px;
    height: 32px;
    color: white;
}

.science-card h3 {
    color: var(--color-text-primary);
    font-size: 1.25rem;
    margin-bottom: 1rem;
}

.science-card p {
    color: var(--color-text-secondary);
    line-height: 1.7;
    font-size: 0.9375rem;
}

.science-card a {
    color: var(--color-primary);
    text-decoration: underline;
    font-weight: 500;
    transition: var(--transition);
}

.science-card a:hover {
    color: var(--color-secondary);
}

.science-footer {
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    color: white;
    padding: 2rem;
    border-radius: var(--radius-lg);
    text-align: center;
}

.science-footer p {
    font-size: 1.125rem;
    line-height: 1.8;
    margin: 0;
}

.science-footer strong {
    color: var(--color-accent);
    font-weight: 700;
}

/* ===== CTA Section ===== */
.cta {
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    color: white;
}

.cta-content {
    text-align: center;
    max-width: 700px;
    margin: 0 auto;
}

.cta h2 {
    color: white;
    font-size: clamp(2rem, 4vw, 2.5rem);
}

.cta p {
    font-size: 1.125rem;
    opacity: 0.95;
}

.cta-buttons {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1rem;
    margin: 2rem 0;
}

.cta-note {
    font-size: 0.875rem;
    opacity: 0.85;
}

/* ===== Footer ===== */
.footer {
    background: var(--color-text-primary);
    color: white;
    padding: 3rem 0 1.5rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 3rem;
    margin-bottom: 2rem;
}

.footer-col h4,
.footer-col h5 {
    color: white;
    margin-bottom: 1.5rem;
}

.footer-col p {
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.7;
}

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

.footer-col ul li {
    margin-bottom: 0.75rem;
}

.footer-col ul li a {
    color: rgba(255, 255, 255, 0.8);
    transition: var(--transition);
}

.footer-col ul li a:hover {
    color: white;
}

.social-links {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
}

.social-links a {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.social-links a:hover {
    background: var(--color-primary);
    transform: translateY(-3px);
}

.social-links svg {
    width: 18px;
    height: 18px;
    fill: white;
}

.footer-bottom {
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
    color: rgba(255, 255, 255, 0.7);
}

/* ===== Responsive Design ===== */
@media (max-width: 1024px) {
    .benefits-content {
        grid-template-columns: 1fr;
    }

    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .step {
        grid-template-columns: auto 1fr;
    }

    .step-visual {
        display: none;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }

    .mobile-menu-toggle {
        display: flex;
    }

    .hero {
        padding: 2rem 0 4rem;
    }

    .hero-title {
        font-size: 2rem;
    }

    .trust-indicators {
        flex-direction: column;
        gap: 1rem;
    }

    .generator-tabs {
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }

    .tab-btn {
        white-space: nowrap;
        padding: 0.75rem 1rem;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }

    .benefits-stats {
        grid-template-columns: 1fr;
    }

    .faq-grid {
        grid-template-columns: 1fr;
    }

    .science-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .science-card {
        padding: 1.5rem;
    }

    .footer-grid {
        grid-template-columns: 1fr;
    }

    .cta-buttons {
        flex-direction: column;
    }

    .cta-buttons .btn {
        width: 100%;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 0.75rem;
    }

    .generator-card {
        padding: 1.5rem;
    }

    .section {
        padding: 3rem 0;
    }
}

/* ===== Utility Classes ===== */
.text-center { text-align: center; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

/* ===== Accessibility ===== */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* ===== Print Styles ===== */
@media print {
    .header,
    .footer,
    .cta,
    .btn {
        display: none;
    }
}