/* ========== CSS Variables — Blue/Teal brand ========== */
:root {
    --bg-primary: #0c1222;
    --bg-secondary: #111827;
    --bg-tertiary: #1a2332;
    --bg-card: #1e293b;
    --text-primary: #e2e8f0;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --accent: #0ea5e9;
    --accent-light: #38bdf8;
    --accent-dark: #0284c7;
    --accent-glow: rgba(14, 165, 233, 0.2);
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --info: #06b6d4;
    --border: #334155;
    --radius: 12px;
    --radius-sm: 8px;
    --shadow: 0 4px 24px rgba(0, 0, 0, 0.35);
    --transition: 0.25s ease;
}

body.light {
    --bg-primary: #f1f5f9;
    --bg-secondary: #ffffff;
    --bg-tertiary: #e2e8f0;
    --bg-card: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --accent-glow: rgba(14, 165, 233, 0.1);
    --border: #cbd5e1;
    --shadow: 0 4px 24px rgba(0, 0, 0, 0.06);
}

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

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    min-height: 100dvh;
    display: flex;
    flex-direction: column;
    transition: background var(--transition), color var(--transition);
    line-height: 1.6;
    padding-left: env(safe-area-inset-left);
    padding-right: env(safe-area-inset-right);
    padding-bottom: env(safe-area-inset-bottom);
}

a { color: var(--accent-light); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ========== Top Bar ========== */
.top-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 20px;
    padding-top: max(10px, env(safe-area-inset-top));
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: background var(--transition);
}

.top-bar .logo {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--accent);
    display: flex;
    align-items: center;
    gap: 6px;
}

.top-bar .logo a { color: var(--accent); text-decoration: none; }

.top-actions {
    display: flex;
    gap: 6px;
    align-items: center;
}

.icon-btn {
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: 5px 10px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.85rem;
    transition: all var(--transition);
    min-width: 44px;
    min-height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

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

.lang-btn {
    font-weight: 600;
    font-size: 0.8rem;
    letter-spacing: 0.02em;
}

/* ========== Main ========== */
main {
    flex: 1;
    max-width: 720px;
    margin: 0 auto;
    padding: 24px 16px;
    width: 100%;
}

main.hub-main { max-width: 960px; }

.page-header {
    text-align: center;
    margin-bottom: 28px;
}

.page-header h1 {
    font-size: 2rem;
    background: linear-gradient(135deg, #0ea5e9, #10b981);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
}

.page-header p {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* ========== Hub ========== */
.hub-toolbar {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.search-input {
    flex: 1;
    min-width: 200px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 10px 14px;
    font-size: 0.95rem;
    color: var(--text-primary);
    outline: none;
    transition: border-color var(--transition);
}

.search-input:focus { border-color: var(--accent); }

.category-tabs {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-bottom: 24px;
}

.category-tab {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    color: var(--text-secondary);
    padding: 8px 16px;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.85rem;
    font-weight: 600;
    transition: all var(--transition);
    min-height: 44px;
}

.category-tab:hover { border-color: var(--accent); color: var(--text-primary); }
.category-tab.active {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 16px;
}

.tool-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 6px;
    transition: all var(--transition);
    text-decoration: none;
    color: inherit;
}

.tool-card:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
    text-decoration: none;
}

.tool-card .card-icon { font-size: 2rem; }
.tool-card .card-title { font-size: 1.05rem; font-weight: 700; color: var(--text-primary); }
.tool-card .card-desc { font-size: 0.85rem; color: var(--text-secondary); line-height: 1.4; }
.tool-card .card-tag {
    display: inline-block;
    margin-top: 4px;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--accent);
    background: var(--accent-glow);
    padding: 2px 8px;
    border-radius: 10px;
    width: fit-content;
}

/* ========== Tool Panel ========== */
.tool-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px 20px;
    margin-bottom: 16px;
}

.form-group {
    margin-bottom: 16px;
}

.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

.form-row {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.form-row .form-group { flex: 1; min-width: 120px; }

.tool-input,
.tool-select {
    width: 100%;
    background: var(--bg-tertiary);
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 10px 14px;
    font-size: 1rem;
    color: var(--text-primary);
    outline: none;
    transition: border-color var(--transition);
}

.tool-input:focus,
.tool-select:focus { border-color: var(--accent); }

.tool-select { cursor: pointer; }

.tool-textarea {
    width: 100%;
    min-height: 160px;
    background: var(--bg-tertiary);
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 12px 14px;
    font-size: 0.95rem;
    font-family: inherit;
    color: var(--text-primary);
    outline: none;
    resize: vertical;
    line-height: 1.6;
    transition: border-color var(--transition);
}

.tool-textarea:focus { border-color: var(--accent); }

.stat-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: 12px;
    margin-top: 16px;
}

.stat-card {
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 14px;
    text-align: center;
}

.stat-card .stat-num {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent);
}

.stat-card .stat-name {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.4px;
    margin-top: 4px;
}

.tip-quick-row {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-bottom: 16px;
}

.tip-quick {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    color: var(--text-secondary);
    padding: 8px 14px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.85rem;
    font-weight: 600;
    min-height: 40px;
}

.tip-quick:hover { border-color: var(--accent); color: var(--text-primary); }
.tip-quick.active { background: var(--accent); border-color: var(--accent); color: #fff; }

.uuid-list { margin-top: 16px; display: flex; flex-direction: column; gap: 8px; }

.uuid-row {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 10px 12px;
}

.uuid-code {
    font-family: Consolas, Monaco, monospace;
    font-size: 0.9rem;
    color: var(--accent);
    word-break: break-all;
    flex: 1;
}

.tool-error {
    background: rgba(239, 68, 68, 0.12);
    border: 1px solid var(--danger);
    border-radius: var(--radius-sm);
    color: var(--danger);
    font-size: 0.9rem;
    padding: 10px 14px;
    margin-bottom: 12px;
}

.tool-error[hidden] { display: none; }

.result-box {
    background: var(--accent-glow);
    border: 1px solid var(--accent);
    border-radius: var(--radius-sm);
    padding: 16px 20px;
    margin-top: 16px;
    text-align: center;
}

.result-box .result-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--accent);
    line-height: 1.2;
}

.result-box .result-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-top: 4px;
}

.result-box .result-detail {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-top: 8px;
}

.result-box.success { border-color: var(--success); background: rgba(16, 185, 129, 0.1); }
.result-box.success .result-value { color: var(--success); }
.result-box.warning { border-color: var(--warning); background: rgba(245, 158, 11, 0.1); }
.result-box.warning .result-value { color: var(--warning); }

/* ========== Buttons ========== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 10px 24px;
    border-radius: var(--radius-sm);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    border: none;
    transition: all var(--transition);
    min-height: 44px;
}

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

.btn-primary:hover { background: var(--accent-dark); transform: translateY(-1px); }

.btn-secondary {
    background: transparent;
    border: 2px solid var(--accent);
    color: var(--accent);
}

.btn-secondary:hover { background: var(--accent); color: #fff; }

.btn-group {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-top: 16px;
}

.btn-sm { padding: 6px 14px; font-size: 0.85rem; min-height: 36px; }

/* ========== Mode Tabs ========== */
.mode-tabs {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
    margin-bottom: 20px;
}

.mode-tab {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    color: var(--text-secondary);
    padding: 8px 14px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.85rem;
    font-weight: 600;
    transition: all var(--transition);
    min-height: 44px;
}

.mode-tab:hover { border-color: var(--accent); color: var(--text-primary); }
.mode-tab.active { background: var(--accent); border-color: var(--accent); color: #fff; }

/* ========== Checkbox / Options ========== */
.option-row {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 10px;
    cursor: pointer;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.option-row input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--accent);
    cursor: pointer;
}

.password-output {
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 1.1rem;
    word-break: break-all;
    background: var(--bg-tertiary);
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 14px;
    min-height: 52px;
    margin-top: 12px;
}

.number-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 12px;
}

.number-chip {
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 8px 14px;
    font-size: 1rem;
    font-weight: 600;
    color: var(--accent);
}

.range-slider {
    width: 100%;
    accent-color: var(--accent);
    margin-top: 4px;
}

/* ========== SEO / FAQ ========== */
.info-section { margin-top: 36px; }
.info-section > h2:first-child {
    font-size: 1.3rem;
    color: var(--accent-light);
    margin-bottom: 12px;
}

.info-intro {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 20px;
}

.faq-list { margin-top: 16px; }

.faq-item {
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    margin-bottom: 8px;
    overflow: hidden;
}

.faq-question {
    width: 100%;
    background: var(--bg-card);
    border: none;
    color: var(--text-primary);
    padding: 14px 16px;
    font-size: 0.95rem;
    font-weight: 600;
    text-align: left;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    transition: background var(--transition);
    min-height: 44px;
}

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

.faq-question::after {
    content: '+';
    font-size: 1.2rem;
    color: var(--accent);
    flex-shrink: 0;
}

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

.faq-answer {
    display: none;
    padding: 0 16px 14px;
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.7;
}

.faq-item.open .faq-answer { display: block; }

.related-tools {
    margin-top: 32px;
    padding-top: 24px;
    border-top: 1px solid var(--border);
}

.related-tools h3 {
    font-size: 1.1rem;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.related-links {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.related-link {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 8px 14px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-primary);
    text-decoration: none;
    transition: all var(--transition);
}

.related-link:hover {
    border-color: var(--accent);
    color: var(--accent);
    text-decoration: none;
}

/* ========== Footer ========== */
footer {
    text-align: center;
    padding: 20px 16px;
    color: var(--text-muted);
    font-size: 0.8rem;
    border-top: 1px solid var(--border);
    margin-top: auto;
}

/* ========== 404 ========== */
.error-panel {
    text-align: center;
    padding: 40px 20px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
}

.error-panel h1 {
    font-size: 4rem;
    color: var(--accent);
    margin-bottom: 8px;
}

/* ========== Calculator ========== */
.calc-display {
    background: var(--bg-tertiary);
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 16px;
    font-size: 2rem;
    font-weight: 700;
    text-align: right;
    min-height: 64px;
    word-break: break-all;
    margin-bottom: 12px;
}

.calc-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
}

.calc-btn {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: 14px 8px;
    border-radius: var(--radius-sm);
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    min-height: 48px;
}

.calc-btn:hover { border-color: var(--accent); }
.calc-btn.op { color: var(--accent); }
.calc-btn.eq { background: var(--accent); border-color: var(--accent); color: #fff; }
.calc-btn.wide { grid-column: span 2; }

.json-status {
    font-size: 0.85rem;
    margin: 8px 0;
    min-height: 1.2em;
}
.json-status.ok { color: var(--success, #22c55e); }
.json-status.err { color: #ef4444; }

.color-preview {
    width: 100%;
    height: 80px;
    border-radius: var(--radius-sm);
    border: 2px solid var(--border);
    margin: 12px 0;
}

.color-values {
    display: grid;
    gap: 8px;
    margin: 12px 0;
    font-family: ui-monospace, monospace;
    font-size: 0.95rem;
}

.qr-wrap {
    text-align: center;
    margin-top: 16px;
}

#qr-canvas {
    max-width: 100%;
    height: auto;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
}

.canvas-wrap {
    width: 100%;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    overflow: hidden;
    touch-action: none;
    background: #fff;
}

#draw-canvas {
    display: block;
    width: 100%;
    cursor: crosshair;
}

.btn-row {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-top: 12px;
}

.btn-row .btn { flex: 1; min-width: 100px; }

.barrage-overlay {
    position: fixed;
    inset: 0;
    z-index: 9999;
    display: flex;
    align-items: center;
    overflow: hidden;
    cursor: pointer;
}

.barrage-overlay[hidden] { display: none !important; }

.barrage-text {
    white-space: nowrap;
    font-weight: 700;
    will-change: transform;
}

body.barrage-active { overflow: hidden; }

.md5-result {
    font-family: ui-monospace, monospace;
    font-size: 1rem;
    word-break: break-all;
    padding: 12px;
    background: var(--bg-tertiary);
    border-radius: var(--radius-sm);
    margin: 12px 0;
}

/* ========== Responsive ========== */
@media (max-width: 600px) {
    .page-header h1 { font-size: 1.6rem; }
    .tools-grid { grid-template-columns: 1fr; }
    .form-row { flex-direction: column; }
    .result-box .result-value { font-size: 1.6rem; }
}