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

:root {
    --primary-color: #2563eb;
    --secondary-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --text-dark: #1f2937;
    --text-light: #6b7280;
    --bg-light: #f9fafb;
    --bg-white: #ffffff;
    --border-color: #e5e7eb;
    --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);
    --border-radius: 8px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-light);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header and Navigation */
header {
    background-color: var(--bg-white);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
}

nav {
    padding: 1rem 0;
}

nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

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

.nav-menu a {
    color: var(--text-dark);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

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

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.hero h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    font-weight: 700;
}

.hero-subtitle {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto;
    opacity: 0.95;
}

/* Sections */
section {
    padding: 4rem 0;
}

section h2 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--text-dark);
    text-align: center;
}

.section-intro {
    text-align: center;
    color: var(--text-light);
    max-width: 700px;
    margin: 0 auto 2rem;
    font-size: 1.1rem;
}

/* Calculator Section */
.calculator-section {
    background-color: var(--bg-white);
}

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

.calculator-form,
.results-container {
    background: var(--bg-white);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
}

.calculator-form h3 {
    color: var(--primary-color);
    margin: 2rem 0 1rem 0;
    font-size: 1.3rem;
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 0.5rem;
}

.calculator-form h3:first-child {
    margin-top: 0;
}

/* Form Styles */
.form-group {
    margin-bottom: 1.5rem;
}

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

.form-group input,
.form-group select {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: border-color 0.3s;
    background-color: var(--bg-white);
    color: var(--text-dark);
}

.form-group input::placeholder {
    color: #9ca3af;
    opacity: 0.8;
}

/* Ensure select elements display properly */
.form-group select,
.input-group select {
    appearance: none;
    -webkit-appearance: none;
    -moz-appearance: none;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right 0.75rem center;
    background-size: 1em;
    padding-right: 2.5rem;
}

/* Number input styling */
input[type="number"] {
    -moz-appearance: textfield;
}

input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

/* Datetime input styling */
input[type="datetime-local"] {
    position: relative;
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
}

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

.input-group input {
    flex: 1;
    min-width: 100px;
}

.input-group select {
    flex: 0 0 auto;
    min-width: 120px;
    max-width: 180px;
}

.form-group small {
    display: block;
    margin-top: 0.25rem;
    color: var(--text-light);
    font-size: 0.875rem;
}

.info-text {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 1rem;
}

/* Drinking Session Cards */
.drinking-session {
    background: var(--bg-light);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    margin-bottom: 1rem;
    border: 2px solid var(--border-color);
    position: relative;
}

.drinking-session h4 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
}

.drinking-session .form-group input,
.drinking-session .form-group select {
    background-color: var(--bg-white);
}

/* Buttons */
.btn-primary,
.btn-secondary,
.btn-remove-session {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    width: 100%;
    margin-top: 0.5rem;
}

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

.btn-primary:hover {
    background: #1d4ed8;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: var(--bg-light);
    color: var(--text-dark);
    border: 2px solid var(--border-color);
}

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

.btn-remove-session {
    background: var(--danger-color);
    color: white;
    margin-top: 1rem;
}

.btn-remove-session:hover {
    background: #dc2626;
}

/* Results Container */
.results-container h3 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
}

.result-card {
    background: var(--bg-light);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    margin-bottom: 1rem;
    border-left: 4px solid var(--primary-color);
}

.result-card.primary-result {
    background: linear-gradient(135deg, #667eea15 0%, #764ba215 100%);
    border-left: 4px solid var(--primary-color);
}

.result-card h4 {
    color: var(--text-dark);
    margin-bottom: 0.5rem;
    font-size: 1rem;
}

.result-value {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-color);
    margin: 0.5rem 0;
}

.result-description {
    color: var(--text-light);
    font-size: 0.9rem;
}

/* Timeline Chart */
.timeline-container {
    margin: 2rem 0;
    padding: 1.5rem;
    background: var(--bg-white);
    border-radius: var(--border-radius);
    border: 2px solid var(--border-color);
}

.timeline-container h4 {
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.timeline-chart {
    position: relative;
    height: 200px;
    background: var(--bg-light);
    border-radius: var(--border-radius);
    overflow: hidden;
}

.timeline-bar {
    position: absolute;
    height: 100%;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 600;
    font-size: 0.9rem;
}

.timeline-legend {
    display: flex;
    gap: 1.5rem;
    margin-top: 1rem;
    flex-wrap: wrap;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
}

.legend-color {
    width: 20px;
    height: 20px;
    border-radius: 4px;
}

/* Disclaimer */
.disclaimer {
    background: #fef3c7;
    border-left: 4px solid var(--warning-color);
    padding: 1rem;
    margin-top: 1.5rem;
    border-radius: var(--border-radius);
    font-size: 0.9rem;
    line-height: 1.6;
}

/* Content Grid */
.content-grid,
.use-cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.content-card,
.use-case-card {
    background: var(--bg-white);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    border-top: 4px solid var(--primary-color);
}

.content-card h3,
.use-case-card h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-size: 1.3rem;
}

.content-card p,
.use-case-card p {
    color: var(--text-dark);
    line-height: 1.8;
    margin-bottom: 1rem;
}

.content-card ul,
.use-case-card ul {
    margin-left: 1.5rem;
    color: var(--text-dark);
}

.content-card li,
.use-case-card li {
    margin-bottom: 0.5rem;
    line-height: 1.8;
}

/* About Section */
.about-section {
    background: var(--bg-white);
}

/* FAQ Section */
.faq-section {
    background: var(--bg-light);
}

.faq-container {
    max-width: 900px;
    margin: 2rem auto 0;
}

.faq-item {
    background: var(--bg-white);
    margin-bottom: 1rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}

.faq-question {
    padding: 1.5rem;
    cursor: pointer;
    background: var(--bg-white);
    transition: background 0.3s;
    font-size: 1.1rem;
    color: var(--text-dark);
    position: relative;
    padding-right: 3rem;
}

.faq-question:hover {
    background: var(--bg-light);
}

.faq-question::after {
    content: '+';
    position: absolute;
    right: 1.5rem;
    top: 50%;
    transform: translateY(-50%);
    font-size: 1.5rem;
    color: var(--primary-color);
    font-weight: 700;
}

.faq-item.active .faq-question::after {
    content: '−';
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
}

.faq-item.active .faq-answer {
    max-height: 1000px;
    transition: max-height 0.5s ease-in;
}

.faq-answer p {
    padding: 0 1.5rem 1.5rem;
    color: var(--text-dark);
    line-height: 1.8;
}

/* Info Section */
.info-section {
    background: var(--bg-white);
}

.tips-section {
    margin-top: 3rem;
}

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

.tip-card {
    background: var(--bg-light);
    padding: 2rem;
    border-radius: var(--border-radius);
    border: 2px solid var(--border-color);
}

.tip-card h4 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.tip-card ul {
    margin-left: 1.5rem;
}

.tip-card li {
    margin-bottom: 0.75rem;
    line-height: 1.6;
}

/* Science Section */
.science-section {
    background: var(--bg-light);
}

.science-content {
    max-width: 900px;
    margin: 2rem auto 0;
    background: var(--bg-white);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
}

.science-content h3 {
    color: var(--primary-color);
    margin-top: 2rem;
    margin-bottom: 1rem;
    font-size: 1.4rem;
}

.science-content h3:first-child {
    margin-top: 0;
}

.science-content p {
    margin-bottom: 1rem;
    line-height: 1.8;
}

.science-content ul {
    margin: 1rem 0 1rem 2rem;
}

.science-content li {
    margin-bottom: 0.75rem;
    line-height: 1.8;
}

/* CTA Section */
.cta-section {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    padding: 4rem 0;
}

.cta-section h2 {
    color: white;
    margin-bottom: 1rem;
}

.cta-section p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.95;
}

.cta-section .btn-primary {
    display: inline-block;
    width: auto;
    padding: 1rem 2rem;
    background: white;
    color: var(--primary-color);
    text-decoration: none;
}

.cta-section .btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.2);
}

/* Footer */
footer {
    background: var(--text-dark);
    color: white;
    padding: 3rem 0 1rem;
}

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

.footer-section h4 {
    margin-bottom: 1rem;
    color: white;
}

.footer-section p {
    color: #d1d5db;
    line-height: 1.6;
}

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

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

.footer-section a {
    color: #d1d5db;
    text-decoration: none;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: white;
}

.footer-bottom {
    border-top: 1px solid #374151;
    padding-top: 2rem;
    text-align: center;
    color: #9ca3af;
}

.footer-bottom p {
    margin-bottom: 0.5rem;
}

.footer-bottom a {
    color: #9ca3af;
    text-decoration: none;
}

.footer-bottom a:hover {
    color: white;
}

/* Responsive Design */
@media (max-width: 968px) {
    .calculator-container {
        grid-template-columns: 1fr;
    }
    
    .results-container {
        order: 2;
    }
    
    .input-group {
        flex-wrap: nowrap;
    }
    
    .input-group select {
        min-width: 100px;
    }
}

@media (max-width: 768px) {
    .hero h2 {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    section h2 {
        font-size: 1.75rem;
    }
    
    .nav-menu {
        gap: 1rem;
        font-size: 0.95rem;
    }
    
    .content-grid,
    .use-cases-grid,
    .tips-grid {
        grid-template-columns: 1fr;
    }
    
    .timeline-chart {
        height: 150px;
    }
    
    .calculator-form,
    .results-container {
        padding: 1.5rem;
    }
    
    .calculator-form h3 {
        font-size: 1.2rem;
    }
    
    .input-group select {
        min-width: 110px;
        font-size: 0.95rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    section {
        padding: 2rem 0;
    }
    
    .hero {
        padding: 2rem 0;
    }
    
    .calculator-form,
    .results-container {
        padding: 1.5rem;
    }
    
    .result-value {
        font-size: 1.5rem;
    }
    
    .nav-menu {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .input-group {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .input-group input,
    .input-group select {
        width: 100%;
        min-width: auto;
    }
    
    .drinking-session {
        padding: 1rem;
    }
    
    .form-group input,
    .form-group select {
        font-size: 16px; /* Prevents zoom on iOS */
    }
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.5s ease-out;
}

/* Print Styles */
@media print {
    header,
    footer,
    .calculator-form,
    .cta-section {
        display: none;
    }
    
    .results-container {
        box-shadow: none;
        border: 1px solid #000;
    }
}