:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-card: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --border: #e2e8f0;
    --error: #ef4444;
    --success: #10b981;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Inter', sans-serif;
}

[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-card: #1e293b;
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --accent: #3b82f6;
    --accent-hover: #60a5fa;
    --border: #334155;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.5);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-body);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden; /* Prevent horizontal scroll */
    width: 100%;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

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

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent);
    text-decoration: none;
}

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

.nav-list {
    display: flex;
    list-style: none;
    gap: 1.5rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    transition: color 0.2s;
}

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

/* Dropdown - STRICT COMPLIANCE: top: 100% */
.dropdown {
    position: relative;
}

.dropdown-menu {
    position: absolute;
    top: 100%; /* Explicitly as requested, NOT calc(100% + 8px) */
    left: 0;
    background-color: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    box-shadow: var(--shadow);
    padding: 1rem;
    min-width: 280px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all 0.2s ease;
    z-index: 1001;
}

.dropdown:hover .dropdown-menu,
.dropdown-toggle:focus + .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.75rem;
}

.dropdown-grid a {
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 0.9rem;
    padding: 0.5rem;
    border-radius: 4px;
    transition: background 0.2s;
}

.dropdown-grid a:hover,
.dropdown-grid a.active {
    background-color: var(--bg-secondary);
    color: var(--accent);
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-primary);
    cursor: pointer;
}

.theme-toggle {
    background: none;
    border: 1px solid var(--border);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    cursor: pointer;
    font-size: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
}

/* Breadcrumb */
.breadcrumb-container {
    padding: 1rem 1.5rem;
}

.breadcrumb {
    display: flex;
    list-style: none;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.breadcrumb a {
    color: var(--accent);
    text-decoration: none;
}

.breadcrumb li:not(:last-child)::after {
    content: "→";
    margin-left: 0.5rem;
    color: var(--text-secondary);
}

/* Hero */
.hero {
    text-align: center;
    padding: 4rem 1.5rem;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
}

.hero h1 {
    font-family: var(--font-heading);
    font-size: clamp(2rem, 5vw, 3rem);
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.hero-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* Reference Section */
.reference-section {
    padding: 2rem 1.5rem;
    margin-bottom: 2rem;
}

.reference-section h2 {
    font-family: var(--font-heading);
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
}

.reference-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1rem;
}

.reference-grid a {
    color: var(--accent);
    text-decoration: none;
    font-size: 0.95rem;
    padding: 0.75rem;
    background-color: var(--bg-secondary);
    border-radius: 6px;
    border: 1px solid var(--border);
    transition: transform 0.2s, border-color 0.2s;
}

.reference-grid a:hover {
    transform: translateY(-2px);
    border-color: var(--accent);
}

/* Calculator */
.calculator-section {
    padding: 2rem 1.5rem;
}

.calculator-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow);
    max-width: 600px;
    margin: 0 auto;
}

.calc-tabs {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    border-bottom: 2px solid var(--border);
}

.tab-btn {
    background: none;
    border: none;
    padding: 0.75rem 1rem;
    font-family: var(--font-body);
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    transition: all 0.2s;
}

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

.calc-form {
    display: none;
}

.calc-form.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

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

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 6px;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 1rem;
    transition: border-color 0.2s;
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-group input.invalid {
    border-color: var(--error);
}

.error-msg {
    display: block;
    color: var(--error);
    font-size: 0.85rem;
    margin-top: 0.25rem;
    min-height: 1.2em;
}

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

.input-group input {
    flex: 1;
}

.input-group select {
    width: 100px;
    flex-shrink: 0;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border-radius: 6px;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.2s;
    border: none;
    font-size: 1rem;
}

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

.btn-primary:hover:not(:disabled) {
    background-color: var(--accent-hover);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-outline {
    background-color: transparent;
    border: 1px solid var(--border);
    color: var(--text-primary);
}

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

.btn-outline-light {
    background-color: transparent;
    border: 1px solid white;
    color: white;
}

.btn-outline-light:hover {
    background-color: white;
    color: var(--accent);
}

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

.btn-block {
    width: 100%;
    margin-top: 1rem;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
}

/* Result Section */
.result-section {
    padding: 2rem 1.5rem;
    max-width: 600px;
    margin: 0 auto;
}

.result-card {
    background-color: var(--bg-card);
    border: 1px solid var(--success);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow);
    text-align: center;
}

.result-card h2 {
    font-family: var(--font-heading);
    color: var(--success);
    margin-bottom: 1.5rem;
}

.result-display {
    display: grid;
    gap: 1rem;
    margin-bottom: 2rem;
    padding: 1.5rem;
    background-color: var(--bg-secondary);
    border-radius: 8px;
}

.result-item {
    display: flex;
    flex-direction: column;
}

.result-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 0.25rem;
}

.result-value {
    font-family: var(--font-heading);
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-primary);
}

.action-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    justify-content: center;
}

/* SEO Content */
.seo-content {
    padding: 3rem 1.5rem;
    max-width: 800px;
}

.seo-content h2 {
    font-family: var(--font-heading);
    margin-bottom: 1.5rem;
    font-size: 2rem;
}

.seo-content p {
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* Features */
.features {
    padding: 3rem 1.5rem;
}

.features h2 {
    font-family: var(--font-heading);
    text-align: center;
    margin-bottom: 2rem;
    font-size: 2rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.feature-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1.5rem;
    text-align: center;
    transition: transform 0.2s;
}

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

.feature-card h3 {
    font-family: var(--font-heading);
    margin-bottom: 0.75rem;
    color: var(--accent);
}

.feature-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* How It Works */
.how-it-works {
    padding: 3rem 1.5rem;
    background-color: var(--bg-secondary);
}

.how-it-works h2 {
    font-family: var(--font-heading);
    text-align: center;
    margin-bottom: 2rem;
    font-size: 2rem;
}

.steps-list {
    max-width: 600px;
    margin: 0 auto;
    padding-left: 1.5rem;
}

.steps-list li {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

.steps-list strong {
    color: var(--text-primary);
}

/* FAQ */
.faq {
    padding: 3rem 1.5rem;
    max-width: 800px;
}

.faq h2 {
    font-family: var(--font-heading);
    text-align: center;
    margin-bottom: 2rem;
    font-size: 2rem;
}

.faq-list details {
    background-color: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    margin-bottom: 1rem;
    padding: 1rem;
    cursor: pointer;
}

.faq-list summary {
    font-weight: 600;
    color: var(--text-primary);
    outline: none;
}

.faq-list details[open] summary {
    margin-bottom: 0.75rem;
    color: var(--accent);
}

.faq-list p {
    color: var(--text-secondary);
    padding-left: 1rem;
    border-left: 3px solid var(--accent);
}

/* CTA */
.cta-section {
    background-color: var(--accent);
    color: white;
    text-align: center;
    padding: 4rem 1.5rem;
}

.cta-section h2 {
    font-family: var(--font-heading);
    font-size: 2rem;
    margin-bottom: 1rem;
}

.cta-section p {
    margin-bottom: 2rem;
    opacity: 0.9;
}

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

/* Footer */
.footer {
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border);
    padding: 3rem 1.5rem 1.5rem;
}

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

.footer-col h4 {
    font-family: var(--font-heading);
    margin-bottom: 1rem;
    color: var(--text-primary);
}

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

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

.footer-col a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.2s;
}

.footer-col a:hover {
    color: var(--accent);
}

.footer-bottom {
    border-top: 1px solid var(--border);
    padding-top: 1.5rem;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.disclaimer {
    margin: 1rem 0;
    font-size: 0.8rem;
    opacity: 0.8;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-top: 1rem;
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
}

.footer-links a:hover {
    color: var(--accent);
}

/* Cookie Banner */
.cookie-banner {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background-color: var(--bg-card);
    border-top: 1px solid var(--border);
    box-shadow: 0 -4px 6px -1px rgba(0, 0, 0, 0.1);
    padding: 1rem 1.5rem;
    z-index: 9999;
    display: none;
}

.cookie-banner.show {
    display: block;
}

.cookie-content {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.cookie-content p {
    flex: 1;
    margin: 0;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.cookie-content a {
    color: var(--accent);
}

.cookie-actions {
    display: flex;
    gap: 0.75rem;
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: block;
    }

    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background-color: var(--bg-card);
        flex-direction: column;
        padding: 2rem;
        transition: left 0.3s ease;
        border-top: 1px solid var(--border);
    }

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

    .nav-list {
        flex-direction: column;
        width: 100%;
        gap: 1rem;
    }

    .dropdown-menu {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        border: none;
        padding-left: 1rem;
        display: none;
    }

    .dropdown.active .dropdown-menu {
        display: block;
    }

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

    .hero h1 {
        font-size: 2rem;
    }

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

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

    .cookie-content {
        flex-direction: column;
        text-align: center;
    }
}