/* ===== CSS Variables & Reset ===== */
:root {
    --color-primary: #4f46e5;
    --color-primary-dark: #4338ca;
    --color-primary-light: #e0e7ff;
    --color-secondary: #0ea5e9;
    --color-bg: #fafbff;
    --color-surface: #ffffff;
    --color-text: #1e293b;
    --color-text-light: #64748b;
    --color-border: #e2e8f0;
    --color-success: #10b981;
    --color-accent: #f59e0b;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
    --shadow-lg: 0 12px 40px rgba(0,0,0,0.12);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --max-width: 1100px;
}

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

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-sans);
    color: var(--color-text);
    background: var(--color-bg);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

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

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

/* ===== Header ===== */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255,255,255,0.92);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.logo {
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 2px;
    font-weight: 800;
    font-size: 1.5rem;
    color: var(--color-text);
}

.logo-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: var(--color-primary);
    color: white;
    border-radius: var(--radius-sm);
    font-size: 1.3rem;
    font-weight: 900;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 8px;
}

.nav-link {
    text-decoration: none;
    color: var(--color-text-light);
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 500;
    transition: all 0.2s;
}

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

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-text);
    border-radius: 2px;
    transition: all 0.3s;
}

/* ===== Hero ===== */
.hero {
    padding: 60px 0 40px;
    text-align: center;
    background: linear-gradient(180deg, var(--color-primary-light) 0%, var(--color-bg) 100%);
}

.hero h1 {
    font-size: clamp(1.8rem, 5vw, 3rem);
    font-weight: 900;
    letter-spacing: -0.03em;
    line-height: 1.15;
    margin-bottom: 12px;
    color: var(--color-text);
}

.hero-subtitle {
    font-size: clamp(1rem, 2.5vw, 1.2rem);
    color: var(--color-text-light);
    max-width: 600px;
    margin: 0 auto 32px;
}

/* ===== Solver Card ===== */
.solver-card {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: 32px;
    box-shadow: var(--shadow-lg);
    max-width: 700px;
    margin: 0 auto;
    text-align: left;
}

.input-group {
    display: flex;
    gap: 10px;
}

.input-group input {
    flex: 1;
    padding: 14px 18px;
    font-size: 1.05rem;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-family: var(--font-sans);
    transition: border-color 0.2s, box-shadow 0.2s;
    outline: none;
}

.input-group input:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 4px rgba(79,70,229,0.1);
}

.btn-primary {
    padding: 14px 28px;
    background: var(--color-primary);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    font-family: var(--font-sans);
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
    white-space: nowrap;
}

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

.btn-primary:active {
    transform: scale(0.97);
}

.input-hint {
    font-size: 0.82rem;
    color: var(--color-text-light);
    margin-top: 8px;
}

/* ===== Filters ===== */
.filters {
    display: flex;
    gap: 16px;
    margin-top: 16px;
    flex-wrap: wrap;
}

.filter-group {
    display: flex;
    align-items: center;
    gap: 6px;
}

.filter-group label {
    font-size: 0.85rem;
    color: var(--color-text-light);
    font-weight: 500;
}

.filter-group select {
    padding: 6px 10px;
    border: 1px solid var(--color-border);
    border-radius: 6px;
    font-size: 0.85rem;
    font-family: var(--font-sans);
    color: var(--color-text);
    background: white;
    cursor: pointer;
}

/* ===== Results ===== */
.results-area {
    margin-top: 24px;
    min-height: 120px;
}

.results-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 40px 20px;
    color: var(--color-text-light);
    text-align: center;
}

.placeholder-icon {
    margin-bottom: 12px;
    opacity: 0.4;
}

.results-stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--color-border);
}

.results-count {
    font-weight: 700;
    font-size: 0.95rem;
    color: var(--color-primary);
}

.results-time {
    font-size: 0.82rem;
    color: var(--color-text-light);
}

.results-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.result-word {
    display: inline-flex;
    align-items: center;
    padding: 8px 16px;
    background: var(--color-primary-light);
    color: var(--color-primary-dark);
    border-radius: 100px;
    font-weight: 600;
    font-size: 0.92rem;
    letter-spacing: 0.02em;
    transition: all 0.15s;
    cursor: default;
}

.result-word:hover {
    background: var(--color-primary);
    color: white;
    transform: translateY(-1px);
}

.result-word.exact-match {
    background: var(--color-primary);
    color: white;
    box-shadow: 0 2px 8px rgba(79,70,229,0.3);
}

.result-word.exact-match:hover {
    background: var(--color-primary-dark);
}

.result-section-label {
    width: 100%;
    font-size: 0.78rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-text-light);
    margin-top: 12px;
    margin-bottom: 4px;
}

.no-results {
    text-align: center;
    padding: 40px 20px;
    color: var(--color-text-light);
}

.no-results h3 {
    font-size: 1.1rem;
    margin-bottom: 8px;
    color: var(--color-text);
}

.loading-spinner {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 40px;
    gap: 8px;
    color: var(--color-text-light);
}

.loading-spinner::before {
    content: '';
    width: 20px;
    height: 20px;
    border: 2px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
}

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

/* ===== Popular Section ===== */
.popular-section {
    padding: 60px 0;
    text-align: center;
}

h2 {
    font-size: clamp(1.4rem, 3.5vw, 2rem);
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 8px;
}

.section-subtitle {
    color: var(--color-text-light);
    margin-bottom: 32px;
    font-size: 1.05rem;
}

.popular-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
}

.popular-chip {
    padding: 10px 22px;
    border: 2px solid var(--color-border);
    border-radius: 100px;
    background: var(--color-surface);
    font-size: 0.95rem;
    font-weight: 600;
    font-family: var(--font-sans);
    color: var(--color-text);
    cursor: pointer;
    transition: all 0.2s;
}

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

/* ===== How It Works ===== */
.how-section {
    padding: 60px 0;
    background: var(--color-surface);
    text-align: center;
}

.steps-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-top: 8px;
}

.step-card {
    padding: 32px 24px;
    border-radius: var(--radius-md);
    background: var(--color-bg);
    text-align: center;
}

.step-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background: var(--color-primary);
    color: white;
    border-radius: 50%;
    font-size: 1.3rem;
    font-weight: 800;
    margin-bottom: 16px;
}

.step-card h3 {
    font-size: 1.1rem;
    margin-bottom: 8px;
}

.step-card p {
    font-size: 0.92rem;
    color: var(--color-text-light);
    line-height: 1.6;
}

/* ===== Use Cases ===== */
.uses-section {
    padding: 60px 0;
    text-align: center;
}

.uses-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    text-align: left;
    margin-top: 8px;
}

.use-card {
    padding: 28px;
    background: var(--color-surface);
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border);
    transition: box-shadow 0.2s, transform 0.2s;
}

.use-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.use-card h3 {
    font-size: 1.05rem;
    margin-bottom: 8px;
    color: var(--color-primary);
}

.use-card p {
    font-size: 0.92rem;
    color: var(--color-text-light);
    line-height: 1.6;
}

/* ===== Links Section ===== */
.links-section {
    padding: 60px 0;
    text-align: center;
}

.links-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    text-align: left;
    margin-top: 8px;
}

.link-card {
    display: block;
    padding: 24px;
    background: var(--color-surface);
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border);
    text-decoration: none;
    color: var(--color-text);
    transition: box-shadow 0.2s, transform 0.2s, border-color 0.2s;
}

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

.link-card h3 {
    font-size: 1rem;
    margin-bottom: 8px;
    color: var(--color-primary);
}

.link-card p {
    font-size: 0.88rem;
    color: var(--color-text-light);
    line-height: 1.6;
    margin-bottom: 12px;
}

.link-url {
    font-size: 0.78rem;
    color: var(--color-secondary);
    font-weight: 500;
}

/* ===== Dictionary Stats ===== */
.dict-stats {
    margin-top: 12px;
    padding: 8px 14px;
    background: var(--color-bg);
    border-radius: var(--radius-sm);
    font-size: 0.82rem;
    color: var(--color-text-light);
}

/* ===== FAQ ===== */
.faq-section {
    padding: 60px 0;
    background: var(--color-surface);
    text-align: center;
}

.faq-list {
    max-width: 720px;
    margin: 0 auto;
    text-align: left;
}

.faq-item {
    border-bottom: 1px solid var(--color-border);
}

.faq-item summary {
    padding: 20px 0;
    cursor: pointer;
    list-style: none;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.faq-item summary::-webkit-details-marker {
    display: none;
}

.faq-item summary::after {
    content: '+';
    font-size: 1.4rem;
    font-weight: 300;
    color: var(--color-text-light);
    transition: transform 0.2s;
    flex-shrink: 0;
    margin-left: 16px;
}

.faq-item[open] summary::after {
    content: '-';
}

.faq-item summary h3 {
    font-size: 1rem;
    font-weight: 600;
}

.faq-item p {
    padding: 0 0 20px;
    font-size: 0.92rem;
    color: var(--color-text-light);
    line-height: 1.7;
}

/* ===== Content Section ===== */
.content-section {
    padding: 60px 0;
}

.content-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
    text-align: left;
    margin-top: 24px;
}

.content-grid h3 {
    font-size: 1.15rem;
    margin-bottom: 12px;
}

.content-grid p {
    font-size: 0.92rem;
    color: var(--color-text-light);
    line-height: 1.7;
    margin-bottom: 12px;
}

/* ===== Footer ===== */
.site-footer {
    background: var(--color-text);
    color: #94a3b8;
    padding: 48px 0 24px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 32px;
    margin-bottom: 32px;
}

.footer-brand p {
    font-size: 0.88rem;
    margin-top: 12px;
    line-height: 1.6;
}

.footer-brand .logo {
    color: white;
}

.footer-brand .logo-icon {
    background: var(--color-primary);
}

.footer-links h4 {
    color: white;
    font-size: 0.9rem;
    margin-bottom: 16px;
}

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

.footer-links li {
    margin-bottom: 8px;
}

.footer-links a {
    color: #94a3b8;
    text-decoration: none;
    font-size: 0.88rem;
    transition: color 0.2s;
}

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

.footer-bottom {
    border-top: 1px solid #334155;
    padding-top: 20px;
    text-align: center;
    font-size: 0.82rem;
}

/* ===== Mobile Responsive ===== */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 64px;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 16px 20px;
        border-bottom: 1px solid var(--color-border);
        box-shadow: var(--shadow-md);
    }

    .nav-links.open {
        display: flex;
    }

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

    .hero {
        padding: 40px 0 24px;
    }

    .solver-card {
        padding: 20px;
    }

    .input-group {
        flex-direction: column;
    }

    .btn-primary {
        width: 100%;
        text-align: center;
    }

    .filters {
        flex-direction: column;
        gap: 10px;
    }

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

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

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

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

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 24px;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 1.6rem;
    }

    .solver-card {
        padding: 16px;
        border-radius: var(--radius-md);
    }
}

/* ===== Active Nav ===== */
.nav-link.active {
    color: var(--color-primary);
    background: var(--color-primary-light);
}

/* ===== Scrabble Tiles ===== */
.tile-grid {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    margin-top: 8px;
}

.tile-row {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
    justify-content: center;
}

.scrabble-tile {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, #f5e6c8, #e8d5a8);
    border: 2px solid #c4a86b;
    border-radius: 6px;
    font-size: 1.2rem;
    font-weight: 800;
    color: #3d2c1a;
    position: relative;
    box-shadow: 1px 2px 4px rgba(0,0,0,0.15);
}

.scrabble-tile sub {
    position: absolute;
    bottom: 3px;
    right: 5px;
    font-size: 0.55rem;
    font-weight: 700;
    color: #6b5232;
}

.scrabble-tile.blank {
    background: linear-gradient(135deg, #e8e8e8, #d0d0d0);
    border-color: #aaa;
    color: #666;
}

.scrabble-tile.blank sub {
    color: #888;
}

/* Scrabble score badge on result words */
.word-score {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 22px;
    height: 20px;
    padding: 0 5px;
    background: rgba(255,255,255,0.3);
    border-radius: 10px;
    font-size: 0.7rem;
    font-weight: 700;
    margin-left: 6px;
}

/* ===== Ad Containers ===== */
/*
 * UX principles:
 * - Reserved heights prevent Cumulative Layout Shift (CLS)
 * - Ads only appear between content sections, never inside the solver
 * - Clean borders and spacing so ads feel like part of the page, not intrusive
 * - Hidden on print
 */
.ad-container {
    display: flex;
    justify-content: center;
    padding: 20px 0;
}

.ad-leaderboard {
    max-width: var(--max-width);
    margin: 0 auto;
    padding-left: 20px;
    padding-right: 20px;
}

.ad-slot {
    width: 100%;
    max-width: 728px;
    min-height: 90px;
    background: var(--color-bg);
    border: 1px dashed var(--color-border);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

/* When an ad loads, remove the placeholder border */
.ad-slot:has(ins),
.ad-slot:has(iframe) {
    border: none;
    background: none;
    min-height: auto;
}

/* On smaller screens, use responsive ad size */
@media (max-width: 768px) {
    .ad-slot {
        max-width: 100%;
        min-height: 100px;
    }
}

/* ===== Print ===== */
@media print {
    .site-header, .site-footer, .filters, .popular-section, .how-section, .ad-container {
        display: none;
    }

    .solver-card {
        box-shadow: none;
        border: 1px solid #ccc;
    }
}