:root {
    --bg: #f4f1ec;
    --card-bg: #ffffff;
    --text: #1e1e1e;
    --text-secondary: #6b6b6b;
    --accent: #f0724a;
    --accent-hover: #e05a30;
    --accent-light: #fff0ea;
    --accent-gradient: linear-gradient(135deg, #f0724a, #f59a6b);
    --blue: #4a90d9;
    --blue-light: #eef4fb;
    --blue-gradient: linear-gradient(135deg, #4a90d9, #6db3f2);
    --border: #e8e3db;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.04), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.05), 0 2px 6px rgba(0,0,0,0.04);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.08), 0 2px 8px rgba(0,0,0,0.04);
    --radius-sm: 10px;
    --radius: 16px;
    --radius-lg: 20px;
    --sidebar-width: 260px;
    --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    font-size: 15px;
    line-height: 1.75;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ── Header ── */
.header {
    background: var(--card-bg);
    border-bottom: 1px solid var(--border);
    padding: 28px 0;
    box-shadow: var(--shadow-sm);
    position: relative;
    z-index: 10;
}

.header-inner {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 44px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
}

.header-brand {
    display: flex;
    align-items: center;
    gap: 14px;
}

.header-logo {
    width: 42px;
    height: 42px;
    border-radius: 12px;
    background: var(--accent-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    color: #fff;
    flex-shrink: 0;
    box-shadow: 0 2px 8px rgba(240,114,74,0.3);
}

.header h1 {
    font-size: 24px;
    font-weight: 700;
    color: var(--text);
    letter-spacing: -0.3px;
}

.version-info {
    display: inline-flex;
    align-items: center;
    gap: 14px;
    padding: 8px 18px;
    font-size: 14px;
    color: var(--text-secondary);
    background: var(--accent-light);
    border: 1px solid #fdd8c8;
    border-radius: 20px;
    font-weight: 500;
}

.version-info strong {
    font-weight: 700;
    color: var(--text);
}

.version-info .sep {
    color: #dcc8b8;
    font-weight: 300;
}

.version-dot {
    display: inline-block;
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: #4ecb71;
    margin-right: 2px;
    animation: pulse-dot 2s ease-in-out infinite;
}

@keyframes pulse-dot {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.3); }
}

/* ── Layout ── */
.layout {
    display: flex;
    min-height: calc(100vh - 90px);
    max-width: 1280px;
    margin: 0 auto;
}

/* ── Sidebar ── */
.sidebar {
    width: var(--sidebar-width);
    background: var(--card-bg);
    border-right: 1px solid var(--border);
    padding: 24px 0;
    flex-shrink: 0;
    box-shadow: var(--shadow-sm);
    position: relative;
    z-index: 5;
}

.menu-group {
    margin-bottom: 16px;
    padding: 0 8px;
}

.menu-parent {
    display: flex;
    align-items: center;
    gap: 10px;
    width: 100%;
    padding: 12px 20px 8px;
    font-size: 16px;
    font-weight: 800;
    color: var(--text);
    background: none;
    border: none;
    text-align: left;
    cursor: default;
    text-transform: uppercase;
    letter-spacing: 2px;
    border-bottom: 2px solid var(--border);
    margin-bottom: 8px;
}

.menu-parent::before {
    content: '';
    display: inline-block;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--accent);
    opacity: 0.7;
}

.menu-parent[data-hidden="true"] {
    display: none;
}

.menu-child {
    display: block;
    width: 100%;
    padding: 9px 16px 9px 28px;
    font-size: 14px;
    color: #999;
    background: none;
    border: none;
    text-align: left;
    cursor: pointer;
    transition: all var(--transition);
    position: relative;
    border-radius: 8px;
    margin-bottom: 1px;
    font-weight: 400;
}

.menu-child[data-hidden="true"] {
    display: none;
}

.menu-child:hover {
    color: var(--accent);
    background: var(--accent-light);
}

.menu-child.active {
    color: #fff;
    background: var(--accent-gradient);
    font-weight: 600;
    box-shadow: 0 2px 10px rgba(240,114,74,0.25);
}

.menu-child.active::before {
    display: none;
}

/* ── Content ── */
.content {
    flex: 1;
    padding: 40px 44px;
    overflow-y: auto;
}

.content .section {
    display: none;
    animation: fadeSlideIn 0.35s ease;
}

.content .section.active {
    display: block;
}

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

/* ── Section Title ── */
.section-title {
    font-size: 24px;
    font-weight: 800;
    color: var(--text);
    margin-bottom: 10px;
    letter-spacing: -0.5px;
    line-height: 1.3;
}

.section-desc {
    font-size: 15px;
    color: #000;
    margin-bottom: 36px;
    padding: 16px 20px;
    background: #fafaf8;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
    line-height: 1.7;
}

/* ── Download Card ── */
.download-item {
    margin-bottom: 24px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px 28px;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition);
}

.download-item:hover {
    box-shadow: var(--shadow-md);
    border-color: #e0d8cc;
}

.download-item:last-child {
    margin-bottom: 0;
}

.download-label {
    font-size: 15px;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 14px;
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.download-label .tag {
    display: inline-block;
    background: var(--accent-light);
    color: var(--accent);
    font-size: 12px;
    font-weight: 600;
    padding: 4px 10px;
    border-radius: 14px;
    letter-spacing: 0.2px;
}

.download-label .tag.recommend {
    background: #e8f5e9;
    color: #2e7d32;
}

.download-label .tag.slow {
    background: #fff3e0;
    color: #e65100;
}

.warn-list .tag {
    display: inline-block;
    background: #e3f0fc;
    color: #1565c0;
    font-weight: 500;
    padding: 3px 10px;
    border-radius: 12px;
    margin: 4px 4px 4px 0;
    font-size: 12px;
}

.download-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: var(--card-bg);
    border: 1.5px solid var(--border);
    border-radius: 12px;
    padding: 12px 18px;
    font-size: 14px;
    color: var(--accent);
    text-decoration: none;
    transition: all var(--transition);
    font-weight: 500;
    word-break: break-all;
}

.download-link:hover {
    background: var(--accent-light);
    border-color: var(--accent);
    box-shadow: 0 2px 12px rgba(240,114,74,0.12);
}

.download-code {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    font-size: 14px;
    font-weight: 600;
    color: #d44;
    margin-top: 10px;
    margin-left: 8px;
    background: #fff5f5;
    padding: 4px 12px;
    border-radius: 8px;
    border: 1px solid #fdd;
}

/* ── Guide ── */
.guide-block {
    margin-bottom: 36px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px 30px;
    box-shadow: var(--shadow-sm);
}

.guide-heading {
    font-size: 15px;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 10px;
    line-height: 1.5;
}

.guide-sub {
    font-size: 15px;
    color: var(--accent);
    font-weight: 600;
    margin-bottom: 10px;
}

.guide-divider {
    height: 1px;
    background: linear-gradient(to right, var(--border), transparent);
    margin: 28px 0;
}

.guide-step {
    display: flex;
    gap: 16px;
    margin-bottom: 22px;
    align-items: flex-start;
}

.step-num {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--accent-gradient);
    color: #fff;
    font-size: 15px;
    font-weight: 700;
    flex-shrink: 0;
    box-shadow: 0 2px 8px rgba(240,114,74,0.3);
}

.step-body {
    flex: 1;
    font-size: 15px;
    line-height: 1.85;
}

.step-body p {
    margin-bottom: 14px;
}

.guide-img {
    display: block;
    max-width: 100%;
    border-radius: 12px;
    border: 1px solid var(--border);
    margin: 14px 0;
    box-shadow: var(--shadow-sm);
}

.guide-note {
    font-size: 14px;
    color: var(--text-secondary);
    background: #fafaf8;
    padding: 10px 14px;
    border-radius: 8px;
    border-left: 3px solid #ddd;
}

.guide-warn {
    background: #fffaf7;
    border: 1.5px solid #fdd8c8;
    border-radius: var(--radius);
    padding: 24px 28px;
    box-shadow: var(--shadow-sm);
}

.guide-ending {
    font-size: 15px;
    color: var(--text-secondary);
    margin-bottom: 8px;
    text-align: center;
    padding: 16px;
}

/* ── Alert Banner ── */
.alert-banner {
    background: linear-gradient(135deg, #fff6f0, #ffede3);
    border: 1.5px solid #fcc8a8;
    border-radius: var(--radius);
    padding: 20px 28px;
    margin-bottom: 32px;
    font-size: 15px;
    font-weight: 700;
    color: #c0392b;
    text-align: center;
    letter-spacing: 0.5px;
    box-shadow: var(--shadow-sm);
    position: relative;
    overflow: hidden;
}

.alert-banner::before {
    content: '';
    position: absolute;
    top: -30px;
    right: -30px;
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: rgba(240,114,74,0.08);
}

.alert-banner::after {
    content: '';
    position: absolute;
    bottom: -20px;
    left: 20px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: rgba(240,114,74,0.05);
}

/* ── Warn List ── */
.warn-list {
    list-style: none;
    padding: 0;
    margin-bottom: 28px;
}

.warn-list li {
    position: relative;
    padding: 20px 24px 20px 52px;
    margin-bottom: 16px;
    background: var(--card-bg);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    font-size: 15px;
    line-height: 1.75;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition);
}

.warn-list li:hover {
    box-shadow: var(--shadow-md);
}

.warn-list li::before {
    content: '💡';
    position: absolute;
    left: 18px;
    top: 20px;
    font-size: 18px;
}

.warn-list li.high {
    background: linear-gradient(135deg, #fff5f5, #ffeded);
    border: 2px solid #fcc;
    font-weight: 600;
    color: #b71c1c;
}

.warn-list li.high::before {
    content: '⚠️';
    font-size: 18px;
}

/* ── Info Block ── */
.info-block {
    margin-bottom: 36px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px 28px;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition);
}

.info-block:hover {
    box-shadow: var(--shadow-md);
}

.info-block h3 {
    display: inline-block;
    font-size: 15px;
    font-weight: 700;
    color: var(--text);
    background: linear-gradient(135deg, #e8f0fa, #dce8f4);
    padding: 6px 14px;
    border-radius: 8px;
    margin-bottom: 14px;
}

.info-block p {
    font-size: 15px;
    line-height: 1.8;
    color: var(--text);
    padding: 4px 0;
}

/* ── Tutorial Links ── */
.tutorial-list {
    list-style: none;
    padding: 0;
    margin-top: 8px;
}

.tutorial-list li {
    margin-bottom: 14px;
    padding: 8px 0;
    font-size: 15px;
}

.tutorial-list a {
    color: var(--accent);
    text-decoration: none;
    font-weight: 600;
    transition: color var(--transition);
}

.tutorial-list a:hover {
    color: var(--accent-hover);
}

.tutorial-list .t-label {
    display: inline-block;
    min-width: 100px;
    color: var(--text-secondary);
}

/* ── Lock Gate (密码保护) ── */
.lock-gate {
    margin-bottom: 20px;
}

.lock-inner {
    background: linear-gradient(135deg, #f8f6f2, #fefdfb);
    border: 2px dashed #d4cfc4;
    border-radius: var(--radius);
    padding: 32px 28px;
    text-align: center;
}

.lock-icon {
    font-size: 36px;
    display: block;
    margin-bottom: 12px;
}

.lock-title {
    font-size: 15px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 20px;
}

.lock-row {
    display: flex;
    justify-content: center;
    gap: 10px;
    max-width: 400px;
    margin: 0 auto;
}

.lock-input {
    flex: 1;
    padding: 10px 16px;
    font-size: 15px;
    border: 1.5px solid var(--border);
    border-radius: 10px;
    outline: none;
    transition: border-color var(--transition);
    font-family: inherit;
}

.lock-input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(240,114,74,0.1);
}

.lock-btn {
    padding: 10px 24px;
    font-size: 15px;
    font-weight: 600;
    color: #fff;
    background: var(--accent-gradient);
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all var(--transition);
    white-space: nowrap;
    font-family: inherit;
}

.lock-btn:hover {
    box-shadow: 0 2px 10px rgba(240,114,74,0.3);
    transform: translateY(-1px);
}

.lock-btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
    transform: none;
}

.lock-error {
    display: none;
    color: #e74c3c;
    font-size: 14px;
    font-weight: 600;
    margin-top: 14px;
}

.lock-content {
    display: none;
}

/* ── Footer ── */
.footer {
    text-align: center;
    font-size: 15px;
    color: #b0a89e;
    padding: 28px 0 36px;
    border-top: 1px solid var(--border);
    background: var(--card-bg);
}

.footer-inner {
    max-width: 1280px;
    margin: 0 auto;
}

.footer a {
    color: inherit;
    text-decoration: none;
}

.footer a:hover {
    text-decoration: underline;
}

/* ── Responsive ── */
@media (max-width: 700px) {
    .header-inner {
        flex-direction: column;
        align-items: flex-start;
    }
    .layout {
        flex-direction: column;
        max-width: 100%;
    }
    .sidebar {
        width: 100%;
        border-right: none;
        border-bottom: 1px solid var(--border);
        padding: 8px 0;
        display: flex;
        overflow-x: auto;
    }
    .menu-group {
        display: flex;
        align-items: center;
        margin: 0;
        padding: 0 4px;
    }
    .menu-parent {
        padding: 8px 10px;
        white-space: nowrap;
        font-size: 12px;
    }
    .menu-child {
        padding: 8px 12px;
        white-space: nowrap;
        font-size: 12px;
        border-radius: 8px;
    }
    .menu-child.active {
        box-shadow: none;
    }
    .content {
        padding: 20px 16px;
    }
    .header {
        padding: 16px 20px;
    }
    .header h1 {
        font-size: 20px;
    }
    .section-title {
        font-size: 22px;
    }
    .download-item,
    .guide-block,
    .info-block,
    .guide-warn {
        padding: 18px 16px;
    }
    .warn-list li {
        padding: 16px 16px 16px 42px;
    }
    .warn-list li::before {
        left: 12px;
        top: 16px;
    }
}