:root {
    --bg: #0a0a0b;
    --bg-soft: #111113;
    --panel: rgba(255, 255, 255, 0.03);
    --panel-strong: rgba(255, 255, 255, 0.05);
    --ink: #ededed;
    --ink-soft: #888;
    --ink-muted: #555;
    --line: rgba(255, 255, 255, 0.08);
    --brand: #818cf8;
    --brand-strong: #a5b4fc;
    --brand-dim: rgba(129, 140, 248, 0.15);
    --accent: #f59e0b;
    --accent-soft: rgba(245, 158, 11, 0.08);
    --cyan: #22d3ee;
    --success: #34d399;
    --success-dim: rgba(52, 211, 153, 0.1);
    --danger: #f87171;
    --danger-dim: rgba(248, 113, 113, 0.1);
    --warning: #fbbf24;
    --warning-dim: rgba(251, 191, 36, 0.08);
    --shadow: 0 0 0 1px var(--line), 0 16px 48px rgba(0, 0, 0, 0.35);
    --gradient: linear-gradient(135deg, #6366f1, #06b6d4);
    --sidebar-bg: #0d0d0f;
    --surface-float: rgba(10, 10, 11, 0.92);
    --overlay-bg: rgba(0, 0, 0, 0.58);
    --code-bg: rgba(255, 255, 255, 0.04);
    --code-fg: #d4d4d8;
    --code-input-bg: rgba(0, 0, 0, 0.32);
    --progress-track: rgba(255, 255, 255, 0.06);
    --tip-cyan-bg: rgba(6, 182, 212, 0.06);
    --mobile-sidebar-shadow: 4px 0 32px rgba(0, 0, 0, 0.5);
    --float-shadow: 0 4px 16px rgba(0, 0, 0, 0.4);
    --card-hover-border: rgba(255, 255, 255, 0.12);
    --card-hover-bg: rgba(255, 255, 255, 0.05);
    --quiz-option-bg: rgba(255, 255, 255, 0.02);
    --quiz-option-hover-bg: rgba(255, 255, 255, 0.05);
    --quiz-option-hover-border: rgba(255, 255, 255, 0.14);
    --page-header-gradient: radial-gradient(ellipse at top right, rgba(99, 102, 241, 0.06), transparent 60%);
    --hero-glow: radial-gradient(circle, rgba(99, 102, 241, 0.08), transparent 60%);
    --scrollbar-thumb: rgba(255, 255, 255, 0.08);
    --ghost-btn-bg: rgba(255, 255, 255, 0.04);
    --ghost-btn-hover-bg: rgba(255, 255, 255, 0.08);
    --btn-ghost-hover-bg: rgba(255, 255, 255, 0.04);
    --btn-ghost-hover-border: rgba(255, 255, 255, 0.14);
    --copy-btn-bg: rgba(255, 255, 255, 0.08);
    --copy-btn-hover-bg: rgba(255, 255, 255, 0.14);
    --editor-header-bg: rgba(255, 255, 255, 0.04);
    --output-area-bg: rgba(255, 255, 255, 0.02);
    --table-th-bg: rgba(255, 255, 255, 0.03);
    --quick-ref-body-th-bg: rgba(255, 255, 255, 0.04);
    --fb-input-bg: rgba(99, 102, 241, 0.12);
    --fb-input-focus-bg: rgba(99, 102, 241, 0.18);
    --fb-input-focus-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
    --progress-card-sidebar-bg: rgba(255, 255, 255, 0.07);
    --progress-card-sidebar-border: rgba(255, 255, 255, 0.1);
    --progress-label-muted: rgba(239, 247, 246, 0.7);
    --progress-percent: #6ee7b7;
    --sidebar-tile: rgba(255, 255, 255, 0.03);
    --sidebar-tile-soft: rgba(255, 255, 255, 0.02);
    --sidebar-hover: rgba(255, 255, 255, 0.04);
}

[data-theme="light"] {
    --bg: #f4f5f8;
    --bg-soft: #e8eaef;
    --panel: rgba(255, 255, 255, 0.72);
    --panel-strong: #ffffff;
    --ink: #111827;
    --ink-soft: #4b5563;
    --ink-muted: #9ca3af;
    --line: rgba(17, 24, 39, 0.1);
    --brand: #4f46e5;
    --brand-strong: #4338ca;
    --brand-dim: rgba(79, 70, 229, 0.12);
    --accent: #d97706;
    --accent-soft: rgba(217, 119, 6, 0.08);
    --cyan: #0891b2;
    --success: #059669;
    --success-dim: rgba(5, 150, 105, 0.1);
    --danger: #dc2626;
    --danger-dim: rgba(220, 38, 38, 0.1);
    --warning: #d97706;
    --warning-dim: rgba(217, 119, 6, 0.1);
    --shadow: 0 0 0 1px var(--line), 0 16px 48px rgba(15, 23, 42, 0.08);
    --gradient: linear-gradient(135deg, #6366f1, #06b6d4);
    --sidebar-bg: #ffffff;
    --surface-float: rgba(255, 255, 255, 0.96);
    --overlay-bg: rgba(15, 23, 42, 0.35);
    --code-bg: #f1f5f9;
    --code-fg: #1e293b;
    --code-input-bg: #f8fafc;
    --progress-track: rgba(15, 23, 42, 0.08);
    --tip-cyan-bg: rgba(6, 182, 212, 0.08);
    --mobile-sidebar-shadow: 4px 0 32px rgba(15, 23, 42, 0.12);
    --float-shadow: 0 4px 16px rgba(15, 23, 42, 0.1);
    --card-hover-border: rgba(17, 24, 39, 0.12);
    --card-hover-bg: rgba(255, 255, 255, 0.95);
    --quiz-option-bg: rgba(15, 23, 42, 0.03);
    --quiz-option-hover-bg: rgba(15, 23, 42, 0.05);
    --quiz-option-hover-border: rgba(17, 24, 39, 0.14);
    --page-header-gradient: radial-gradient(ellipse at top right, rgba(99, 102, 241, 0.08), transparent 60%);
    --hero-glow: radial-gradient(circle, rgba(99, 102, 241, 0.12), transparent 60%);
    --scrollbar-thumb: rgba(17, 24, 39, 0.15);
    --ghost-btn-bg: rgba(15, 23, 42, 0.04);
    --ghost-btn-hover-bg: rgba(15, 23, 42, 0.08);
    --btn-ghost-hover-bg: rgba(15, 23, 42, 0.05);
    --btn-ghost-hover-border: rgba(17, 24, 39, 0.14);
    --copy-btn-bg: rgba(15, 23, 42, 0.06);
    --copy-btn-hover-bg: rgba(15, 23, 42, 0.1);
    --editor-header-bg: rgba(15, 23, 42, 0.04);
    --output-area-bg: rgba(15, 23, 42, 0.03);
    --table-th-bg: rgba(15, 23, 42, 0.04);
    --quick-ref-body-th-bg: rgba(15, 23, 42, 0.05);
    --fb-input-bg: rgba(79, 70, 229, 0.1);
    --fb-input-focus-bg: rgba(79, 70, 229, 0.14);
    --fb-input-focus-shadow: 0 0 0 3px rgba(79, 70, 229, 0.12);
    --progress-card-sidebar-bg: rgba(15, 23, 42, 0.05);
    --progress-card-sidebar-border: rgba(17, 24, 39, 0.12);
    --progress-label-muted: var(--ink-soft);
    --progress-percent: #059669;
    --sidebar-tile: rgba(15, 23, 42, 0.04);
    --sidebar-tile-soft: rgba(15, 23, 42, 0.03);
    --sidebar-hover: rgba(15, 23, 42, 0.07);
}

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

html {
    color-scheme: dark;
}

html[data-theme="light"] {
    color-scheme: light;
}

body {
    min-height: 100vh;
    color: var(--ink);
    background: var(--bg);
    font-family: -apple-system, BlinkMacSystemFont, "Inter", "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    color: var(--brand);
    transition: color 0.15s;
}

a:hover {
    color: var(--brand-strong);
}

::selection {
    background: var(--brand-dim);
    color: var(--ink);
}

/* ===================== LAYOUT ===================== */
.layout {
    display: flex;
    min-height: 100vh;
}

/* ===================== MOBILE MENU BUTTON ===================== */
.mobile-menu-btn {
    display: none;
    position: fixed;
    top: 14px;
    left: 14px;
    z-index: 1001;
    width: 44px;
    height: 44px;
    border: 1px solid var(--line);
    border-radius: 12px;
    background: var(--surface-float);
    backdrop-filter: blur(12px);
    color: var(--ink);
    font-size: 1.2rem;
    cursor: pointer;
    box-shadow: var(--float-shadow);
    transition: transform 0.15s, background 0.15s;
    align-items: center;
    justify-content: center;
}

.mobile-menu-btn:active {
    transform: scale(0.92);
    background: var(--panel-strong);
}

.theme-toggle-btn {
    position: fixed;
    top: 14px;
    right: 14px;
    z-index: 1002;
    width: 44px;
    height: 44px;
    border: 1px solid var(--line);
    border-radius: 12px;
    background: var(--surface-float);
    backdrop-filter: blur(12px);
    color: var(--ink);
    font-size: 1.15rem;
    line-height: 1;
    cursor: pointer;
    box-shadow: var(--float-shadow);
    transition: transform 0.15s, background 0.15s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle-btn:hover {
    background: var(--panel-strong);
}

.theme-toggle-btn:active {
    transform: scale(0.92);
}

.sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    z-index: 998;
    background: var(--overlay-bg);
    backdrop-filter: blur(4px);
}

/* ===================== SIDEBAR ===================== */
.sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: 280px;
    height: 100vh;
    overflow-y: auto;
    padding: 24px 16px 36px;
    background: var(--sidebar-bg);
    border-right: 1px solid var(--line);
    color: var(--ink);
    scrollbar-width: thin;
    scrollbar-color: var(--scrollbar-thumb) transparent;
    z-index: 999;
    transition: transform 0.3s ease;
}

.logo-card {
    display: flex;
    flex-direction: column;
    gap: 12px;
    padding: 14px 16px 16px;
    border-radius: 16px;
    background: var(--sidebar-tile);
    border: 1px solid var(--line);
    margin-bottom: 16px;
}

.logo-card-top {
    display: flex;
    justify-content: flex-start;
    align-items: center;
    min-height: 28px;
}

/* 课程标题区：用色条区分路线，替代原 emoji logo-mark（与首页 course-card 同色） */
.logo-card-body {
    padding: 2px 0 2px 12px;
    border-left: 3px solid var(--course-accent, var(--brand));
    border-radius: 2px;
}

/* 所有课程侧栏共用：返回学习门户首页（顶栏右侧紧凑幽灵按钮） */
.course-home-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    width: auto;
    max-width: 100%;
    box-sizing: border-box;
    margin: 0;
    padding: 6px 11px;
    border-radius: 999px;
    border: 1px solid transparent;
    background: transparent;
    color: var(--ink-muted);
    text-decoration: none;
    font-size: 0.78rem;
    font-weight: 600;
    letter-spacing: -0.02em;
    line-height: 1.2;
    transition:
        background 0.18s ease,
        border-color 0.18s ease,
        color 0.18s ease,
        box-shadow 0.18s ease,
        transform 0.18s ease;
}

.course-home-link__ico {
    width: 15px;
    height: 15px;
    flex-shrink: 0;
    opacity: 0.85;
    transition: opacity 0.18s ease, transform 0.18s ease;
}

.course-home-link:hover {
    background: var(--sidebar-tile-soft);
    border-color: var(--line);
    color: var(--ink-soft);
    box-shadow: none;
}

.course-home-link:hover .course-home-link__ico {
    opacity: 1;
    color: var(--brand-strong);
    transform: translateX(-1px);
}

.course-home-link:active {
    opacity: 0.88;
}

.course-home-link:focus-visible {
    outline: 2px solid var(--brand);
    outline-offset: 2px;
}

.logo-card-body h1 {
    font-size: 1.28rem;
    font-weight: 700;
    margin: 0 0 4px;
    letter-spacing: -0.02em;
    color: var(--ink);
    line-height: 1.25;
}

.logo-card-body p {
    margin: 0;
    color: var(--ink-soft);
    font-size: 0.86rem;
    line-height: 1.45;
}

.side-meta {
    margin: 14px 0 20px;
    padding: 12px 14px;
    background: var(--sidebar-tile-soft);
    border-radius: 12px;
    border: 1px solid var(--line);
    font-size: 0.84rem;
    color: var(--ink-soft);
}

.side-meta strong {
    color: var(--ink);
}

/* -- Nav Groups (collapsible) -- */
.nav-group {
    margin-bottom: 4px;
}

.nav-group-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 10px;
    border-radius: 8px;
    cursor: pointer;
    user-select: none;
    transition: background 0.15s;
}

.nav-group-header:hover {
    background: var(--sidebar-hover);
}

.nav-title {
    font-size: 0.72rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 600;
}

.nav-group-arrow {
    font-size: 0.65rem;
    color: var(--ink-muted);
    transition: transform 0.2s ease;
}

.nav-group.open .nav-group-arrow {
    transform: rotate(90deg);
}

.nav-group-body {
    overflow: hidden;
    max-height: 0;
    transition: max-height 0.28s ease;
}

.nav-group.open .nav-group-body {
    max-height: 1200px;
}

.nav-item {
    display: block;
    width: 100%;
    text-align: left;
    background: transparent;
    color: var(--ink-soft);
    border: 0;
    border-left: 2px solid transparent;
    padding: 7px 12px 7px 16px;
    border-radius: 8px;
    margin: 1px 0;
    cursor: pointer;
    transition: all 0.15s ease;
    font-size: 0.88rem;
    line-height: 1.4;
}

.nav-item:hover {
    background: var(--sidebar-hover);
    color: var(--ink);
}

.nav-item.active {
    background: var(--brand-dim);
    border-left-color: var(--brand);
    color: var(--brand-strong);
}

.nav-item.completed::after {
    content: "✓";
    float: right;
    color: var(--success);
    font-weight: 700;
    font-size: 0.82rem;
}

/* ===================== MAIN ===================== */
.main {
    flex: 1;
    margin-left: 280px;
    padding: 36px 32px 56px;
}

.page {
    display: none;
    max-width: 860px;
    margin: 0 auto;
}

.page.active {
    display: block;
}

/* ===================== PAGE SHELL ===================== */
.page-shell {
    background: var(--panel);
    border: 1px solid var(--line);
    border-radius: 20px;
    overflow: hidden;
}

.page-header {
    padding: 36px 40px 28px;
    border-bottom: 1px solid var(--line);
    background: var(--page-header-gradient);
}

.eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 5px 12px;
    border-radius: 999px;
    background: var(--brand-dim);
    color: var(--brand);
    font-size: 0.78rem;
    font-weight: 600;
    margin-bottom: 14px;
    letter-spacing: 0.03em;
}

.page-header h1,
.hero-card h1 {
    font-size: clamp(1.6rem, 3.2vw, 2.4rem);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 12px;
    letter-spacing: -0.03em;
    color: var(--ink);
}

.page-header p {
    max-width: 700px;
    color: var(--ink-soft);
    font-size: 1rem;
    line-height: 1.65;
}

.page-content {
    padding: 28px 40px 40px;
}

/* ===================== CARDS & BLOCKS ===================== */
.progress-card,
.grid-card,
.tip,
.warning,
.success,
.exercise,
.mini-quiz,
.resource-list,
.code-editor,
.table-wrap,
.quick-ref,
.fill-blank,
.task-block {
    border-radius: 14px;
    border: 1px solid var(--line);
    background: var(--panel-strong);
}

.progress-card {
    padding: 16px 18px;
    margin-bottom: 20px;
}

.sidebar .progress-card {
    background: var(--progress-card-sidebar-bg);
    border-color: var(--progress-card-sidebar-border);
}

.sidebar .progress-label {
    color: var(--progress-label-muted);
}

.sidebar #courseProgressText {
    color: var(--progress-percent);
}

.progress-label {
    display: flex;
    justify-content: space-between;
    gap: 14px;
    margin-bottom: 10px;
    color: var(--ink-soft);
    font-size: 0.9rem;
}

.progress-bar {
    width: 100%;
    height: 6px;
    background: var(--progress-track);
    border-radius: 999px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    width: 0;
    background: var(--gradient);
    border-radius: 999px;
    transition: width 0.4s ease;
}

.grid-2,
.grid-3 {
    display: grid;
    gap: 14px;
    margin: 20px 0;
}

.grid-2 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.grid-3 {
    grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid-card {
    padding: 18px;
}

.grid-card h3 {
    margin-bottom: 8px;
    font-size: 0.98rem;
    font-weight: 600;
    color: var(--ink);
}

.grid-card p,
.grid-card li {
    color: var(--ink-soft);
    font-size: 0.92rem;
}

.resource-list li {
    color: var(--ink-soft);
    font-size: 0.92rem;
}

h2 {
    font-size: 1.4rem;
    font-weight: 700;
    margin: 32px 0 12px;
    letter-spacing: -0.02em;
    color: var(--ink);
}

.page-content > h2:first-of-type {
    /* 实战等页面里，header 后紧跟第一个 h2；
       全局 h2 margin-top=32px 会造成“顶部大空白”观感问题。 */
    margin-top: 0 !important;
}

h3 {
    font-size: 1.05rem;
    font-weight: 600;
    margin: 22px 0 8px;
}

p + p {
    margin-top: 10px;
}

ul, ol {
    padding-left: 22px;
    margin: 10px 0;
}

li + li {
    margin-top: 6px;
}

li {
    color: var(--ink-soft);
}

/* ===================== CALLOUTS ===================== */
.tip,
.warning,
.success {
    padding: 14px 18px;
    margin: 18px 0;
    border-left: 3px solid transparent;
    font-size: 0.93rem;
}

.tip {
    background: var(--tip-cyan-bg);
    border-left-color: var(--cyan);
    color: var(--ink-soft);
}

.warning {
    background: var(--warning-dim);
    border-left-color: var(--warning);
    color: var(--ink-soft);
}

.success {
    background: var(--success-dim);
    border-left-color: var(--success);
    color: var(--ink-soft);
}

.status-pill {
    display: inline-block;
    padding: 3px 10px;
    border-radius: 999px;
    font-size: 0.78rem;
    font-weight: 600;
    background: var(--brand-dim);
    color: var(--brand);
    letter-spacing: 0.02em;
}

/* ===================== CODE ===================== */
.code-block,
.editor-textarea,
.output-area {
    font-family: "SFMono-Regular", "Cascadia Code", "Monaco", "Menlo", "Consolas", monospace;
}

.code-block {
    position: relative;
    background: var(--code-bg);
    border: 1px solid var(--line);
    color: var(--code-fg);
    padding: 20px 18px 18px;
    border-radius: 12px;
    margin: 16px 0;
    white-space: pre;
    overflow-x: auto;
    line-height: 1.65;
    font-size: 0.87rem;
}

.copy-btn,
.run-btn,
.quiz-btn,
.btn,
.ghost-btn {
    cursor: pointer;
    transition: all 0.15s ease;
}

.copy-btn,
.run-btn,
.quiz-btn {
    border: 0;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.82rem;
}

.copy-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    padding: 5px 10px;
    background: var(--copy-btn-bg);
    color: var(--ink-soft);
    border: 1px solid var(--line);
}

.copy-btn:hover {
    background: var(--copy-btn-hover-bg);
    color: var(--ink);
}

.code-editor {
    margin: 18px 0;
    overflow: hidden;
}

.editor-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    background: var(--editor-header-bg);
    border-bottom: 1px solid var(--line);
}

.editor-title {
    font-size: 0.85rem;
    color: var(--ink-soft);
    font-family: "SFMono-Regular", "Monaco", monospace;
}

.run-btn {
    padding: 7px 14px;
    background: var(--gradient);
    color: #fff;
}

.run-btn:hover {
    opacity: 0.9;
    transform: translateY(-1px);
}

.editor-textarea {
    width: 100%;
    min-height: 160px;
    padding: 16px 18px;
    border: 0;
    outline: none;
    resize: vertical;
    background: var(--code-input-bg);
    color: var(--code-fg);
    font-size: 0.85rem;
    line-height: 1.65;
}

.output-area {
    min-height: 56px;
    padding: 14px 16px;
    background: var(--output-area-bg);
    color: var(--ink-soft);
    border-top: 1px solid var(--line);
    font-size: 0.85rem;
}

.output-area.error {
    color: var(--danger);
}

/* ===================== EXERCISE & QUIZ ===================== */
.exercise,
.mini-quiz,
.resource-list {
    padding: 18px 20px;
    margin: 20px 0;
}

.exercise-title {
    font-weight: 600;
    margin-bottom: 10px;
    font-size: 0.95rem;
    color: var(--ink);
}

.quiz-options {
    display: grid;
    gap: 8px;
    margin: 14px 0;
}

.quiz-option {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    padding: 10px 14px;
    border-radius: 10px;
    border: 1px solid var(--line);
    background: var(--quiz-option-bg);
    cursor: pointer;
    font-size: 0.92rem;
    color: var(--ink-soft);
    transition: all 0.15s;
}

.quiz-option:hover {
    background: var(--quiz-option-hover-bg);
    border-color: var(--quiz-option-hover-border);
    color: var(--ink);
}

.quiz-btn {
    padding: 8px 16px;
    background: var(--gradient);
    color: #ffffff;
    margin-top: 6px;
}

.quiz-result {
    margin-top: 10px;
    font-size: 0.9rem;
}

.quiz-msg--ok {
    color: var(--success);
}

.quiz-msg--err {
    color: var(--danger);
}

.quiz-msg--muted {
    color: var(--ink-muted);
}

/* ===================== TABLE ===================== */
table {
    width: 100%;
    border-collapse: collapse;
}

.table-wrap {
    overflow-x: auto;
    overflow-y: hidden;
    margin: 18px 0;
}

th, td {
    padding: 12px 14px;
    text-align: left;
    border-bottom: 1px solid var(--line);
    vertical-align: top;
    font-size: 0.9rem;
}

th {
    background: var(--table-th-bg);
    color: var(--ink-soft);
    font-weight: 600;
    font-size: 0.84rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

td {
    color: var(--ink-soft);
}

td code {
    background: var(--brand-dim);
    color: var(--brand-strong);
    padding: 2px 7px;
    border-radius: 5px;
    font-size: 0.84rem;
    font-family: "SFMono-Regular", "Monaco", monospace;
}

/* ===================== QUICK REF ===================== */
.quick-ref {
    margin: 24px 0;
    overflow: hidden;
}

.quick-ref-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 13px 18px;
    background: var(--gradient);
    color: #ffffff;
    cursor: pointer;
    user-select: none;
}

.quick-ref-header h3 {
    margin: 0;
    font-size: 0.92rem;
    color: #fff;
    font-weight: 600;
}

.quick-ref-toggle {
    font-size: 0.72rem;
    opacity: 0.8;
    transition: transform 0.2s;
}

.quick-ref.open .quick-ref-toggle {
    transform: rotate(180deg);
}

.quick-ref-body {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

.quick-ref.open .quick-ref-body {
    max-height: 4000px;
}

.quick-ref-body table {
    border-radius: 0;
}

.quick-ref-body th {
    background: var(--quick-ref-body-th-bg);
}

/* ===================== FILL-IN-BLANK ===================== */
.fill-blank {
    margin: 20px 0;
    padding: 20px;
}

.fill-blank .fb-title {
    font-weight: 600;
    margin-bottom: 14px;
    font-size: 0.95rem;
    color: var(--ink);
}

.fill-blank .fb-code {
    background: var(--code-input-bg);
    color: var(--code-fg);
    padding: 16px 18px;
    border-radius: 10px;
    border: 1px solid var(--line);
    font-family: "SFMono-Regular", "Monaco", monospace;
    font-size: 0.85rem;
    line-height: 1.7;
    white-space: pre-wrap;
    margin-bottom: 14px;
}

.fill-blank input[type="text"] {
    display: inline-block;
    background: var(--fb-input-bg);
    border: 1.5px dashed var(--brand);
    border-radius: 5px;
    color: var(--brand-strong);
    font-family: "SFMono-Regular", "Monaco", monospace;
    font-size: 0.85rem;
    padding: 1px 8px;
    min-width: 80px;
    outline: none;
    transition: all 0.15s;
    vertical-align: baseline;
}

.fill-blank input[type="text"]:focus {
    border-color: var(--brand-strong);
    background: var(--fb-input-focus-bg);
    box-shadow: var(--fb-input-focus-shadow);
}

.fill-blank input[type="text"].correct {
    border-color: var(--success);
    background: var(--success-dim);
    color: var(--success);
}

.fill-blank input[type="text"].wrong {
    border-color: var(--danger);
    background: var(--danger-dim);
    color: var(--danger);
}

.fb-check-btn {
    padding: 7px 16px;
    background: var(--gradient);
    color: #fff;
    border: 0;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.85rem;
    transition: all 0.15s;
    margin-right: 8px;
}

.fb-check-btn:hover {
    opacity: 0.9;
    transform: translateY(-1px);
}

.fb-reveal-btn {
    padding: 7px 16px;
    background: transparent;
    color: var(--ink-soft);
    border: 1px solid var(--line);
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.85rem;
    transition: all 0.15s;
}

.fb-reveal-btn:hover {
    background: var(--btn-ghost-hover-bg);
    border-color: var(--btn-ghost-hover-border);
}

.fb-result {
    margin-top: 12px;
    font-size: 0.9rem;
}

/* ===================== TASK BLOCK ===================== */
.task-block {
    margin: 20px 0;
    padding: 20px;
    border-left: 3px solid var(--accent);
    background: var(--accent-soft);
}

.task-block .task-title {
    font-weight: 600;
    font-size: 0.95rem;
    margin-bottom: 10px;
    color: var(--accent);
}

.task-block .task-desc {
    color: var(--ink-soft);
    margin-bottom: 14px;
    font-size: 0.93rem;
}

.task-expected {
    margin-top: 14px;
}

.task-expected summary {
    cursor: pointer;
    color: var(--brand);
    font-weight: 600;
    font-size: 0.88rem;
    padding: 6px 0;
    user-select: none;
}

.task-expected summary:hover {
    color: var(--brand-strong);
}

.task-expected .expected-body {
    margin-top: 10px;
    background: var(--code-input-bg);
    color: var(--code-fg);
    padding: 14px 16px;
    border-radius: 10px;
    border: 1px solid var(--line);
    font-family: "SFMono-Regular", "Monaco", monospace;
    font-size: 0.84rem;
    line-height: 1.6;
    white-space: pre-wrap;
}

/* ===================== BTN ROW ===================== */
.btn-row {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 28px;
}

.btn,
.ghost-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: 10px;
    font-weight: 600;
    text-decoration: none;
    font-size: 0.9rem;
    border: 0;
}

.btn {
    background: var(--gradient);
    color: #ffffff;
    box-shadow: 0 4px 16px rgba(99, 102, 241, 0.25);
}

.btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 8px 24px rgba(99, 102, 241, 0.35);
}

.ghost-btn {
    background: var(--ghost-btn-bg);
    color: var(--ink-soft);
    border: 1px solid var(--line);
}

.ghost-btn:hover {
    background: var(--ghost-btn-hover-bg);
    border-color: var(--btn-ghost-hover-border);
    color: var(--ink);
}

/* ===================== PORTAL (index.html) ===================== */
.portal {
    --portal-display: "Iowan Old Style", "Palatino Linotype", "Book Antiqua", "Songti SC", serif;
    --portal-body: "Avenir Next", "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    max-width: 1180px;
    margin: 0 auto;
    padding: 32px 24px 64px;
    position: relative;
    font-family: var(--portal-body);
}

.portal::before {
    content: "";
    position: fixed;
    inset: 0;
    z-index: -1;
    pointer-events: none;
    background:
        radial-gradient(ellipse 80% 50% at 50% -20%, rgba(99, 102, 241, 0.14), transparent 55%),
        radial-gradient(ellipse 60% 40% at 100% 30%, rgba(6, 182, 212, 0.08), transparent 50%),
        radial-gradient(ellipse 50% 35% at 0% 70%, rgba(245, 158, 11, 0.06), transparent 45%);
}

.portal::after {
    content: "";
    position: fixed;
    inset: 0;
    z-index: -1;
    pointer-events: none;
    opacity: 0.22;
    background-image:
        linear-gradient(rgba(255, 255, 255, 0.035) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
    background-size: 30px 30px;
    mask-image: radial-gradient(circle at center, #000 30%, transparent 85%);
}

[data-theme="light"] .portal::before {
    background:
        radial-gradient(ellipse 80% 50% at 50% -15%, rgba(99, 102, 241, 0.12), transparent 55%),
        radial-gradient(ellipse 60% 40% at 100% 25%, rgba(6, 182, 212, 0.07), transparent 50%),
        radial-gradient(ellipse 50% 35% at 0% 65%, rgba(245, 158, 11, 0.05), transparent 45%);
}

[data-theme="light"] .portal::after {
    opacity: 0.16;
    background-image:
        linear-gradient(rgba(15, 23, 42, 0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(15, 23, 42, 0.045) 1px, transparent 1px);
}

.portal h1,
.portal h2,
.portal .portal-brand-title {
    font-family: var(--portal-display);
}

.portal-top {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 28px;
}

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

.portal-mark {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 66px;
    height: 66px;
    padding: 5px;
    border-radius: 18px;
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid var(--line);
    box-shadow: 0 12px 28px rgba(15, 23, 42, 0.14);
}

.portal-logo {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 14px;
}

.portal-logo-light {
    display: none;
}

[data-theme="light"] .portal-logo-dark {
    display: none;
}

[data-theme="light"] .portal-logo-light {
    display: block;
}

.portal-brand-text {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.portal-brand-title {
    font-size: 1.05rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--ink);
}

.portal-brand-sub {
    font-size: 0.84rem;
    color: var(--ink-soft);
}

.portal-tagline {
    font-size: 0.88rem;
    color: var(--ink-muted);
    padding: 8px 14px;
    border-radius: 999px;
    border: 1px solid var(--line);
    background: var(--panel);
}

.hero-card {
    background:
        radial-gradient(circle at top left, rgba(255, 255, 255, 0.03), transparent 34%),
        linear-gradient(145deg, rgba(255, 255, 255, 0.04), rgba(255, 255, 255, 0.015));
    border: 1px solid var(--line);
    border-radius: 30px;
    padding: 48px 42px;
    margin-bottom: 24px;
    position: relative;
    overflow: hidden;
}

.portal .hero-card {
    padding: 0;
    margin-bottom: 28px;
    box-shadow: var(--shadow);
}

.hero-card-inner {
    position: relative;
    z-index: 1;
    padding: 38px 40px;
}

.hero-grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(320px, 0.82fr);
    gap: 32px;
    align-items: stretch;
}

.hero-copy {
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.hero-copy .eyebrow {
    width: fit-content;
}

.portal .hero-card h1 {
    /* max-width: 8ch; */
    font-size: clamp(2.4rem, 4.6vw, 4.2rem);
    line-height: 1.02;
    margin-bottom: 14px;
    background: linear-gradient(135deg, #eef2ff 12%, #a7ddff 62%, #f0ddb0 100%);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

[data-theme="light"] .portal .hero-card h1 {
    background: linear-gradient(135deg, #312e81 10%, #0f766e 55%, #b45309 100%);
    -webkit-background-clip: text;
    background-clip: text;
}

.hero-orbit {
    position: absolute;
    inset: -40% -30% auto auto;
    width: min(520px, 90vw);
    height: min(520px, 90vw);
    border-radius: 50%;
    background: conic-gradient(from 200deg, rgba(99, 102, 241, 0.22), rgba(6, 182, 212, 0.12), rgba(245, 158, 11, 0.1), rgba(99, 102, 241, 0.22));
    opacity: 0.45;
    filter: blur(2px);
    pointer-events: none;
    animation: portal-orbit-spin 28s linear infinite;
}

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

@media (prefers-reduced-motion: reduce) {
    .hero-orbit,
    .hero-console::before,
    .hero-tags span {
        animation: none;
    }
}

.hero-card::before {
    content: "";
    position: absolute;
    inset: auto -18% -38% auto;
    width: 420px;
    height: 420px;
    background:
        radial-gradient(circle, rgba(255, 255, 255, 0.03), transparent 58%),
        var(--hero-glow);
    pointer-events: none;
    z-index: 0;
    opacity: 0.7;
}

.hero-lead {
    max-width: 34rem;
    color: var(--ink-soft);
    font-size: 1rem;
    line-height: 1.72;
}

.hero-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin: 22px 0 8px;
}

.hero-meta span {
    display: inline-flex;
    align-items: center;
    min-height: 34px;
    padding: 0 12px;
    border-radius: 999px;
    border: 1px solid var(--line);
    background: rgba(255, 255, 255, 0.035);
    color: var(--ink-soft);
    font-size: 0.84rem;
}

.hero-actions {
    margin-top: 18px;
}

.hero-caption {
    margin-top: 16px;
    color: var(--ink-muted);
    font-size: 0.9rem;
    max-width: 34rem;
}

.hero-console {
    position: relative;
    overflow: hidden;
    padding: 18px 18px 16px;
    border-radius: 22px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    background:
        linear-gradient(180deg, rgba(10, 13, 20, 0.84), rgba(17, 21, 30, 0.72)),
        radial-gradient(circle at top right, rgba(59, 130, 246, 0.12), transparent 36%);
    box-shadow: 0 18px 42px rgba(0, 0, 0, 0.22);
}

[data-theme="light"] .hero-console {
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.94), rgba(242, 245, 252, 0.88)),
        radial-gradient(circle at top right, rgba(59, 130, 246, 0.12), transparent 36%);
    box-shadow: 0 20px 50px rgba(15, 23, 42, 0.1);
}

.hero-console::before {
    content: "";
    position: absolute;
    inset: 0;
    opacity: 0.1;
    background: linear-gradient(transparent, rgba(255, 255, 255, 0.06), transparent);
    transform: translateY(-100%);
    animation: portal-scan 7s linear infinite;
    pointer-events: none;
}

@keyframes portal-scan {
    to {
        transform: translateY(100%);
    }
}

.hero-console-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 14px;
}

.console-kicker,
.console-mode {
    display: inline-flex;
    align-items: center;
    border-radius: 999px;
    padding: 7px 10px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    font-size: 0.72rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.console-kicker {
    color: #8bd8ff;
    background: rgba(56, 189, 248, 0.12);
}

.console-mode {
    color: #f8d47a;
    background: rgba(245, 158, 11, 0.12);
}

[data-theme="light"] .console-kicker {
    color: #0f766e;
    background: rgba(15, 118, 110, 0.1);
}

[data-theme="light"] .console-mode {
    color: #b45309;
    background: rgba(217, 119, 6, 0.1);
}

.console-route {
    list-style: none;
    margin: 0;
    padding: 0;
    display: grid;
    gap: 8px;
}

.console-route li {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 14px;
    align-items: start;
    padding: 12px 0;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    color: rgba(255, 255, 255, 0.82);
}

.console-route li:first-child {
    border-top: 0;
    padding-top: 0;
}

[data-theme="light"] .console-route li {
    color: rgba(15, 23, 42, 0.82);
    border-top-color: rgba(15, 23, 42, 0.08);
}

.console-index {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 36px;
    height: 36px;
    border-radius: 12px;
    font-family: "SFMono-Regular", "Cascadia Code", monospace;
    font-size: 0.76rem;
    color: #f8fafc;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.86), rgba(14, 165, 233, 0.76));
    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.18);
}

.console-route strong {
    display: block;
    margin-bottom: 2px;
    font-size: 0.92rem;
    color: #ffffff;
}

.console-route p {
    margin: 0;
    font-size: 0.88rem;
    line-height: 1.58;
    color: rgba(255, 255, 255, 0.64);
}

[data-theme="light"] .console-route strong {
    color: var(--ink);
}

[data-theme="light"] .console-route p {
    color: rgba(15, 23, 42, 0.62);
}

.hero-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 18px;
}

.hero-tags span {
    display: inline-flex;
    align-items: center;
    min-height: 30px;
    padding: 0 10px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.72);
    font-size: 0.78rem;
    letter-spacing: 0.02em;
    animation: none;
}

[data-theme="light"] .hero-tags span {
    background: rgba(15, 23, 42, 0.05);
    border-color: rgba(15, 23, 42, 0.08);
    color: rgba(15, 23, 42, 0.78);
}

.hero-tags span:nth-child(2n) {
    animation-delay: -1.2s;
}

.hero-tags span:nth-child(3n) {
    animation-delay: -2.1s;
}

@keyframes portal-float {
    50% {
        transform: translateY(-4px);
    }
}

.mission-strip {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
    margin-bottom: 28px;
}

.mission-card {
    position: relative;
    overflow: hidden;
    padding: 22px 20px 20px;
    border-radius: 22px;
    border: 1px solid var(--line);
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.02)),
        var(--panel);
}

.mission-card::after {
    content: "";
    position: absolute;
    inset: auto -18% -30% auto;
    width: 140px;
    height: 140px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.16), transparent 68%);
    pointer-events: none;
}

.mission-mark {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 52px;
    height: 30px;
    margin-bottom: 18px;
    padding: 0 12px;
    border-radius: 999px;
    background: var(--brand-dim);
    color: var(--brand-strong);
    font-size: 0.76rem;
    font-weight: 700;
    letter-spacing: 0.08em;
}

.mission-card h3 {
    margin: 0 0 8px;
    font-size: 1.02rem;
}

.mission-card p {
    color: var(--ink-soft);
    font-size: 0.92rem;
}

.journey-picker {
    margin-bottom: 28px;
    padding: 24px;
    border-radius: 26px;
    border: 1px solid var(--line);
    background:
        linear-gradient(135deg, rgba(99, 102, 241, 0.08), transparent 30%),
        linear-gradient(180deg, var(--panel-strong), var(--panel));
    box-shadow: var(--shadow);
}

.section-heading {
    display: grid;
    gap: 8px;
    margin-bottom: 18px;
}

.section-kicker {
    display: inline-flex;
    width: fit-content;
    align-items: center;
    padding: 6px 11px;
    border-radius: 999px;
    background: var(--ghost-btn-bg);
    border: 1px solid var(--line);
    color: var(--ink-muted);
    font-size: 0.72rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.section-heading h2 {
    margin: 0;
    font-size: clamp(1.75rem, 3vw, 2.6rem);
    line-height: 1.05;
}

.section-desc {
    max-width: 720px;
    color: var(--ink-soft);
    font-size: 0.98rem;
}

.journey-options {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.journey-option {
    border: 1px solid var(--line);
    border-radius: 999px;
    background: var(--ghost-btn-bg);
    color: var(--ink-soft);
    padding: 11px 16px;
    font: inherit;
    font-size: 0.92rem;
    cursor: pointer;
    transition: transform 0.18s, border-color 0.18s, background 0.18s, color 0.18s;
}

.journey-option:hover {
    transform: translateY(-1px);
    color: var(--ink);
    border-color: var(--brand);
}

.journey-option.is-active {
    background: var(--gradient);
    color: #fff;
    border-color: transparent;
    box-shadow: 0 10px 24px rgba(99, 102, 241, 0.24);
}

.journey-copy {
    margin-top: 14px;
    color: var(--ink-soft);
    font-size: 0.95rem;
}

.course-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
}

.course-card {
    position: relative;
    overflow: hidden;
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.05), transparent 42%),
        var(--panel);
    border: 1px solid var(--line);
    border-radius: 24px;
    padding: 26px;
    transition: transform 0.22s, border-color 0.22s, background 0.22s, box-shadow 0.22s, opacity 0.22s;
    scroll-margin-top: 88px;
    border-left: 4px solid var(--course-accent, var(--line));
}

.course-card::before {
    content: "";
    position: absolute;
    inset: auto -18% -30% auto;
    width: 180px;
    height: 180px;
    border-radius: 50%;
    background: radial-gradient(circle, color-mix(in srgb, var(--course-accent, var(--brand)) 18%, transparent), transparent 68%);
    pointer-events: none;
    opacity: 0.9;
}

.course-card[data-accent="python"],
.logo-card[data-accent="python"] { --course-accent: #eab308; }

.course-card[data-accent="java"],
.logo-card[data-accent="java"] { --course-accent: #f97316; }

.course-card[data-accent="mysql"],
.logo-card[data-accent="mysql"] { --course-accent: #3b82f6; }

.course-card[data-accent="redis"],
.logo-card[data-accent="redis"] { --course-accent: #ef4444; }

.course-card[data-accent="devops"],
.logo-card[data-accent="devops"] { --course-accent: #14b8a6; }

.course-card[data-accent="ai"],
.logo-card[data-accent="ai"] { --course-accent: #a855f7; }

.course-card:hover {
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.08), transparent 42%),
        var(--card-hover-bg);
    border-color: var(--card-hover-border);
    border-left-color: var(--course-accent, var(--brand));
    transform: translateY(-4px);
    box-shadow: 0 22px 42px rgba(15, 23, 42, 0.1);
}

.course-card.is-featured {
    border-color: color-mix(in srgb, var(--course-accent, var(--brand)) 40%, var(--line));
    box-shadow: 0 18px 34px rgba(15, 23, 42, 0.08);
}

.course-card.is-muted {
    opacity: 0.5;
    transform: scale(0.985);
}

.course-card h2 {
    margin: 10px 0 8px;
    font-size: 1.6rem;
    letter-spacing: -0.03em;
}

.course-card p {
    color: var(--ink-soft);
    font-size: 0.95rem;
}

.course-card .status-pill {
    margin-bottom: 8px;
}

.course-points {
    list-style: none;
    margin: 18px 0 0;
    padding: 0;
    display: grid;
    gap: 10px;
}

.course-points li {
    position: relative;
    padding-left: 18px;
    color: var(--ink-soft);
    font-size: 0.92rem;
}

.course-points li::before {
    content: "";
    position: absolute;
    top: 0.7em;
    left: 0;
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--course-accent, var(--brand));
    box-shadow: 0 0 0 4px color-mix(in srgb, var(--course-accent, var(--brand)) 16%, transparent);
}

.course-card-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 18px;
}

.course-card-meta span {
    display: inline-flex;
    align-items: center;
    min-height: 30px;
    padding: 0 10px;
    border-radius: 999px;
    font-size: 0.8rem;
    color: var(--ink-soft);
    background: var(--ghost-btn-bg);
    border: 1px solid var(--line);
}

/* ===================== RESPONSIVE ===================== */

@media (max-width: 980px) {
    .mobile-menu-btn {
        display: flex;
    }

    .sidebar-overlay.visible {
        display: block;
    }

    .sidebar {
        position: fixed;
        width: 280px;
        height: 100vh;
        transform: translateX(-100%);
        box-shadow: var(--mobile-sidebar-shadow);
    }

    .sidebar.open {
        transform: translateX(0);
    }

    .main {
        margin-left: 0;
        padding: 20px 16px 40px;
        padding-top: 68px;
    }

    .layout {
        display: block;
    }

    .page-header,
    .page-content {
        padding-left: 20px;
        padding-right: 20px;
    }

    .progress-label {
        flex-direction: column;
        align-items: flex-start;
    }

    .grid-2,
    .grid-3,
    .course-grid {
        grid-template-columns: 1fr;
    }

    .portal {
        padding: 20px 14px 40px;
    }

    .hero-card {
        padding: 28px 24px;
    }

    .portal .hero-card {
        padding: 0;
    }

    .hero-card-inner {
        padding: 28px 24px;
    }

    .hero-grid,
    .mission-strip {
        grid-template-columns: 1fr;
    }

    .portal .hero-card h1 {
        max-width: 10ch;
        font-size: clamp(2.1rem, 8vw, 3.1rem);
    }

    .course-card {
        padding: 20px;
    }

    .code-block {
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }
}

@media (max-width: 640px) {
    body {
        line-height: 1.65;
        font-size: 15px;
    }

    .mobile-menu-btn {
        top: 10px;
        left: 10px;
        width: 40px;
        height: 40px;
        font-size: 1.1rem;
        border-radius: 10px;
    }

    .main {
        padding: 12px 10px 32px;
        padding-top: 58px;
    }

    .sidebar {
        width: 84vw;
        max-width: 300px;
        padding: 16px 14px 20px;
    }

    .page-shell,
    .logo-card,
    .side-meta,
    .hero-card,
    .course-card,
    .grid-card,
    .progress-card,
    .exercise,
    .mini-quiz,
    .resource-list,
    .code-editor,
    .table-wrap,
    .quick-ref,
    .fill-blank,
    .task-block {
        border-radius: 12px;
    }

    .page-shell {
        border-radius: 16px;
    }

    .page-header {
        padding: 20px 16px 16px;
    }

    .page-header h1 {
        font-size: 1.35rem;
        line-height: 1.25;
    }

    .page-header p {
        font-size: 0.92rem;
    }

    .page-content {
        padding: 16px 14px 22px;
    }

    h2 {
        font-size: 1.2rem;
        margin: 22px 0 10px;
    }

    .btn-row {
        flex-direction: column;
        align-items: stretch;
    }

    .btn,
    .ghost-btn {
        justify-content: center;
        width: 100%;
        padding: 11px 16px;
        font-size: 0.88rem;
    }

    .code-block {
        padding: 14px 12px;
        font-size: 0.8rem;
        border-radius: 10px;
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }

    .copy-btn {
        position: static;
        display: inline-flex;
        margin-bottom: 8px;
        font-size: 0.78rem;
        padding: 4px 10px;
    }

    .editor-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
        padding: 10px 14px;
    }

    .editor-textarea {
        min-height: 130px;
        padding: 12px;
        font-size: 0.8rem;
    }

    .output-area {
        padding: 10px 12px;
        font-size: 0.8rem;
    }

    .run-btn,
    .quiz-btn,
    .fb-check-btn {
        width: 100%;
        text-align: center;
    }

    .table-wrap {
        margin: 12px 0;
    }

    th, td {
        min-width: 90px;
        padding: 9px 10px;
        font-size: 0.83rem;
    }

    td code {
        font-size: 0.78rem;
        padding: 1px 5px;
    }

    .grid-card {
        padding: 14px;
    }

    .grid-card h3 {
        font-size: 0.92rem;
    }

    .tip,
    .warning,
    .success {
        padding: 12px 14px;
        font-size: 0.88rem;
    }

    .exercise,
    .mini-quiz,
    .resource-list {
        padding: 14px;
    }

    .fill-blank {
        padding: 14px;
    }

    .fill-blank .fb-code {
        padding: 12px;
        font-size: 0.8rem;
    }

    .fill-blank input[type="text"] {
        font-size: 0.8rem;
        min-width: 60px;
    }

    .task-block {
        padding: 14px;
    }

    .task-expected .expected-body {
        padding: 10px 12px;
        font-size: 0.8rem;
    }

    .quick-ref-header {
        padding: 11px 14px;
    }

    .quick-ref-header h3 {
        font-size: 0.88rem;
    }

    .quiz-option {
        padding: 9px 12px;
        font-size: 0.87rem;
    }

    .progress-card {
        padding: 12px 14px;
    }

    .nav-item {
        padding: 7px 10px 7px 16px;
        font-size: 0.85rem;
    }

    .logo-card h1 {
        font-size: 1.25rem;
    }

    .portal {
        padding: 14px 10px 28px;
    }

    .hero-card {
        padding: 20px 16px;
        border-radius: 18px;
    }

    .portal .hero-card {
        padding: 0;
    }

    .hero-card-inner {
        padding: 20px 16px;
    }

    .hero-card h1 {
        font-size: 1.4rem;
        line-height: 1.25;
    }

    .hero-lead {
        font-size: 0.88rem;
    }

    .portal-top {
        flex-direction: column;
        align-items: flex-start;
    }

    .portal .hero-card h1,
    .section-heading h2 {
        max-width: none;
        font-size: clamp(2rem, 10vw, 2.6rem);
    }

    .hero-meta {
        gap: 8px;
    }

    .hero-console {
        padding: 16px;
        border-radius: 18px;
    }

    .hero-console-head {
        flex-direction: column;
        align-items: flex-start;
    }

    .portal-mark {
        width: 58px;
        height: 58px;
        padding: 4px;
    }

    .journey-options {
        display: grid;
        grid-template-columns: 1fr;
    }

    .journey-option {
        width: 100%;
        text-align: left;
    }

    .course-card {
        padding: 16px 14px;
    }

    .course-card h2 {
        font-size: 1.15rem;
    }

    .course-card-meta {
        gap: 6px;
    }

    .journey-picker {
        padding: 18px 16px;
        border-radius: 20px;
    }
}