/* ============================================================
   SkillHub.mobi — macOS Glassmorphism Theme
   Black / White / Gray · Breathing Interactions · Performance First
   ============================================================ */

:root {
    /* --- Palette --- */
    --bg-primary: #f5f5f7;
    --bg-secondary: #ffffff;
    --bg-glass: rgba(255, 255, 255, 0.72);
    --bg-glass-hover: rgba(255, 255, 255, 0.85);
    --bg-card: rgba(255, 255, 255, 0.6);
    --bg-code: rgba(0, 0, 0, 0.04);
    --border-color: rgba(0, 0, 0, 0.08);
    --border-glass: rgba(255, 255, 255, 0.5);
    --text-primary: #1d1d1f;
    --text-secondary: #6e6e73;
    --text-tertiary: #86868b;
    --accent: #000000;
    --accent-soft: rgba(0, 0, 0, 0.06);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.08);
    --radius-sm: 10px;
    --radius-md: 14px;
    --radius-lg: 20px;
    --blur-nav: 20px;
    --transition-breath: 0.4s cubic-bezier(0.25, 0.1, 0.25, 1);
    --transition-fast: 0.2s ease;
    --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", "PingFang SC", "PingFang TC", "Hiragino Sans", "Noto Sans SC", "Noto Sans TC", "Noto Sans JP", sans-serif;
}

/* --- Dark Mode --- */
[data-bs-theme="dark"] {
    --bg-primary: #000000;
    --bg-secondary: #1c1c1e;
    --bg-glass: rgba(28, 28, 30, 0.72);
    --bg-glass-hover: rgba(44, 44, 46, 0.85);
    --bg-card: rgba(28, 28, 30, 0.6);
    --bg-code: rgba(255, 255, 255, 0.06);
    --border-color: rgba(255, 255, 255, 0.08);
    --border-glass: rgba(255, 255, 255, 0.1);
    --text-primary: #f5f5f7;
    --text-secondary: #a1a1a6;
    --text-tertiary: #6e6e73;
    --accent: #ffffff;
    --accent-soft: rgba(255, 255, 255, 0.06);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.25);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.35);
}

/* --- Base --- */
* { box-sizing: border-box; }

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    letter-spacing: -0.01em;
    transition: background-color var(--transition-breath), color var(--transition-breath);
    min-height: 100vh;
    overflow-x: hidden;
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    letter-spacing: -0.025em;
    color: var(--text-primary);
}

.text-secondary-custom { color: var(--text-secondary); }
.text-tertiary { color: var(--text-tertiary); }

/* --- Navbar (Glass — small area, GPU ok) --- */
.navbar-glass {
    background: var(--bg-glass);
    -webkit-backdrop-filter: saturate(180%) blur(var(--blur-nav));
    backdrop-filter: saturate(180%) blur(var(--blur-nav));
    border-bottom: 1px solid var(--border-color);
    transition: background var(--transition-breath);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.navbar-glass .navbar-brand {
    font-weight: 700;
    font-size: 1.25rem;
    letter-spacing: -0.03em;
    color: var(--text-primary);
}

.navbar-glass .nav-link {
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    padding: 0.5rem 0.85rem;
    border-radius: var(--radius-sm);
    transition: color var(--transition-fast), background var(--transition-fast);
}

.navbar-glass .nav-link:hover,
.navbar-glass .nav-link.active {
    color: var(--text-primary);
    background: var(--accent-soft);
}

/* --- Theme & Lang Toggle --- */
.btn-icon {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border-color);
    background: var(--bg-glass);
    color: var(--text-secondary);
    font-size: 0.9rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-icon:hover {
    background: var(--accent-soft);
    color: var(--text-primary);
    transform: scale(1.05);
}

.lang-dropdown .dropdown-menu {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-md);
    min-width: 120px;
}

.lang-dropdown .dropdown-item {
    color: var(--text-secondary);
    font-size: 0.85rem;
    padding: 0.4rem 0.85rem;
    border-radius: 6px;
    margin: 2px 4px;
    transition: all var(--transition-fast);
}

.lang-dropdown .dropdown-item:hover,
.lang-dropdown .dropdown-item.active {
    background: var(--accent-soft);
    color: var(--text-primary);
}

/* --- Hero --- */
.hero-section {
    padding: 4rem 0 3rem;
    text-align: center;
}

.hero-section h1 {
    font-size: clamp(1.8rem, 5vw, 2.8rem);
    font-weight: 700;
    letter-spacing: -0.035em;
    margin-bottom: 0.6rem;
    opacity: 0;
    transform: translateY(12px);
    animation: breatheIn 0.8s var(--transition-breath) forwards;
}

.hero-section p {
    font-size: clamp(1rem, 2.5vw, 1.2rem);
    color: var(--text-secondary);
    opacity: 0;
    transform: translateY(12px);
    animation: breatheIn 0.8s 0.15s var(--transition-breath) forwards;
}

/* --- Search Bar (Glass — focused, small) --- */
.search-glass {
    background: var(--bg-glass);
    border: 1px solid var(--border-color);
    border-radius: 50px;
    padding: 4px;
    display: flex;
    align-items: center;
    max-width: 520px;
    margin: 1.5rem auto 0;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
    opacity: 0;
    transform: translateY(12px);
    animation: breatheIn 0.8s 0.3s var(--transition-breath) forwards;
}

.search-glass:focus-within {
    border-color: rgba(0, 0, 0, 0.2);
    box-shadow: 0 0 0 4px rgba(0, 0, 0, 0.04);
}

[data-bs-theme="dark"] .search-glass:focus-within {
    border-color: rgba(255, 255, 255, 0.2);
    box-shadow: 0 0 0 4px rgba(255, 255, 255, 0.04);
}

.search-glass input {
    flex: 1;
    border: none;
    background: transparent;
    padding: 0.55rem 1rem;
    font-size: 0.95rem;
    color: var(--text-primary);
    outline: none;
    font-family: var(--font-sans);
}

.search-glass input::placeholder {
    color: var(--text-tertiary);
}

.search-glass button {
    border: none;
    background: var(--accent);
    color: var(--bg-primary);
    padding: 0.55rem 1.4rem;
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: opacity var(--transition-fast);
    font-family: var(--font-sans);
}

.search-glass button:hover {
    opacity: 0.8;
}

/* --- Cards (Fake glass — no blur, great perf) --- */
.skill-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    transition: transform var(--transition-breath), box-shadow var(--transition-breath), background var(--transition-breath);
    cursor: pointer;
    text-decoration: none;
    display: block;
    color: inherit;
}

.skill-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
    background: var(--bg-glass-hover);
    color: inherit;
    text-decoration: none;
}

.skill-card .card-title {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.4rem;
    letter-spacing: -0.02em;
}

.skill-card .card-desc {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.5;
    margin-bottom: 0.75rem;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.skill-card .card-meta {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 0.78rem;
    color: var(--text-tertiary);
}

.skill-card .card-meta span {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
}

/* --- Tag / Badge --- */
.tag {
    display: inline-block;
    font-size: 0.72rem;
    font-weight: 500;
    padding: 0.2rem 0.6rem;
    border-radius: 50px;
    background: var(--accent-soft);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    transition: all var(--transition-fast);
}

.tag:hover {
    color: var(--text-primary);
}

.tag.active {
    background: var(--accent);
    color: var(--bg-primary);
    border-color: var(--accent);
}

/* --- Section --- */
.section-title {
    font-size: 1.35rem;
    font-weight: 600;
    margin-bottom: 1.25rem;
    letter-spacing: -0.03em;
}

.section-block {
    margin-bottom: 2.5rem;
}

/* --- Ranking --- */
.rank-row {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.9rem 1rem;
    border-radius: var(--radius-sm);
    transition: background var(--transition-fast);
    text-decoration: none;
    color: inherit;
}

.rank-row:hover {
    background: var(--accent-soft);
    color: inherit;
    text-decoration: none;
}

.rank-num {
    font-size: 1.3rem;
    font-weight: 700;
    width: 2rem;
    text-align: center;
    color: var(--text-tertiary);
    flex-shrink: 0;
}

.rank-row:nth-child(1) .rank-num,
.rank-row:nth-child(2) .rank-num,
.rank-row:nth-child(3) .rank-num {
    color: var(--text-primary);
}

.rank-info { flex: 1; min-width: 0; }

.rank-info .name {
    font-weight: 600;
    font-size: 0.95rem;
    letter-spacing: -0.01em;
}

.rank-info .desc {
    font-size: 0.8rem;
    color: var(--text-tertiary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.rank-stats {
    font-size: 0.8rem;
    color: var(--text-secondary);
    text-align: right;
    flex-shrink: 0;
}

/* --- Detail Page --- */
.detail-header {
    padding: 2.5rem 0 1.5rem;
}

.detail-header h1 {
    font-size: clamp(1.5rem, 4vw, 2.2rem);
    font-weight: 700;
}

.code-block {
    background: var(--bg-code);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 1rem 1.25rem;
    font-family: "SF Mono", "Fira Code", "Menlo", monospace;
    font-size: 0.85rem;
    color: var(--text-primary);
    position: relative;
    overflow-x: auto;
    white-space: pre-wrap;
    word-break: break-all;
}

.code-block .copy-btn {
    position: absolute;
    top: 0.6rem;
    right: 0.6rem;
    font-size: 0.75rem;
    padding: 0.25rem 0.65rem;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    background: var(--bg-secondary);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-family: var(--font-sans);
}

.code-block .copy-btn:hover {
    color: var(--text-primary);
    background: var(--accent-soft);
}

/* --- Info Grid --- */
.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 0.75rem;
    margin: 1.5rem 0;
}

.info-item {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 0.85rem 1rem;
}

.info-item .label {
    font-size: 0.72rem;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    margin-bottom: 0.2rem;
}

.info-item .value {
    font-size: 0.95rem;
    font-weight: 600;
}

/* --- About Page --- */
.about-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    text-align: center;
    transition: transform var(--transition-breath), box-shadow var(--transition-breath);
}

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

.about-card .icon {
    font-size: 2rem;
    margin-bottom: 0.75rem;
}

.about-card h3 {
    font-size: 1rem;
    margin-bottom: 0.4rem;
}

.about-card p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.55;
}

/* --- Category pills --- */
.cat-pills {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

/* --- Pagination --- */
.page-link-custom {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    border-radius: var(--radius-sm);
    padding: 0.45rem 0.9rem;
    font-size: 0.85rem;
    text-decoration: none;
    transition: all var(--transition-fast);
    display: inline-block;
}

.page-link-custom:hover {
    background: var(--accent-soft);
    color: var(--text-primary);
}

.page-link-custom.active {
    background: var(--accent);
    color: var(--bg-primary);
    border-color: var(--accent);
}

/* --- Footer --- */
.footer-area {
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    margin-top: 3rem;
    color: var(--text-tertiary);
    font-size: 0.8rem;
    text-align: center;
}

/* --- Animations (GPU-only: transform + opacity) --- */
@keyframes breatheIn {
    from {
        opacity: 0;
        transform: translateY(12px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    opacity: 0;
    transform: translateY(10px);
    animation: breatheIn 0.6s var(--transition-breath) forwards;
}

.fade-in-d1 { animation-delay: 0.05s; }
.fade-in-d2 { animation-delay: 0.1s; }
.fade-in-d3 { animation-delay: 0.15s; }
.fade-in-d4 { animation-delay: 0.2s; }
.fade-in-d5 { animation-delay: 0.25s; }
.fade-in-d6 { animation-delay: 0.3s; }
.fade-in-d7 { animation-delay: 0.35s; }
.fade-in-d8 { animation-delay: 0.4s; }

/* --- Responsive --- */
@media (max-width: 576px) {
    .hero-section { padding: 2.5rem 0 2rem; }
    .section-title { font-size: 1.15rem; }
    .search-glass { margin: 1rem auto 0; }
    .info-grid { grid-template-columns: repeat(2, 1fr); }
    .rank-row { padding: 0.7rem 0.5rem; }
}

/* --- Scrollbar (webkit) --- */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

/* --- Selection --- */
::selection {
    background: rgba(0, 0, 0, 0.12);
}

[data-bs-theme="dark"] ::selection {
    background: rgba(255, 255, 255, 0.15);
}

/* --- Separator line for rank list --- */
.rank-list > a + a {
    border-top: 1px solid var(--border-color);
}