/*
 * Stickman UI V3
 * Visual-only layer. Keep page IDs, data attributes, API calls and business JS unchanged.
 */
:root {
    --primary-50: #edf4ff;
    --primary-100: #dceaff;
    --primary-200: #bdd3ff;
    --primary-300: #8fb2f4;
    --primary-400: #5d8ee8;
    --primary-500: #326fe8;
    --primary-600: #285dcc;
    --primary-700: #204ba7;
    --primary-800: #1b3d83;
    --primary-900: #172f63;
    --accent-500: #d88432;
    --accent-600: #b96b20;
    --success: #278d68;
    --warning: #c88728;
    --error: #c84b4b;
    --info: #326fe8;
    --bg-primary: #f5f6f8;
    --bg-secondary: #ffffff;
    --bg-tertiary: #eef1f5;
    --text-primary: #17243a;
    --text-secondary: #718097;
    --text-tertiary: #98a4b5;
    --text-muted: #718097;
    --border-primary: #dfe4eb;
    --border-secondary: #c7d1de;
    --border-color: #dfe4eb;
    --shadow-color: rgba(28, 43, 68, .08);
    --primary-gradient: #326fe8;
    --primary-gradient-hover: #285dcc;
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 10px;
    --radius-xl: 12px;
    --radius-2xl: 14px;
    --shadow-sm: 0 1px 2px rgba(28, 43, 68, .05);
    --shadow-md: 0 8px 24px rgba(28, 43, 68, .06);
    --shadow-lg: 0 14px 34px rgba(28, 43, 68, .08);
    --shadow-xl: 0 18px 46px rgba(28, 43, 68, .12);
    --shadow-2xl: 0 24px 64px rgba(28, 43, 68, .16);
    --shadow-glow-sm: none;
    --shadow-glow-md: none;
    --shadow-glow-lg: none;
}

[data-theme="dark"] {
    --bg-primary: #111a29;
    --bg-secondary: #172235;
    --bg-tertiary: #202e43;
    --text-primary: #edf3fb;
    --text-secondary: #a5b2c5;
    --text-tertiary: #718199;
    --text-muted: #9aa9bd;
    --border-primary: #2b3b53;
    --border-secondary: #3b4e69;
    --border-color: #2b3b53;
    --shadow-color: rgba(0, 0, 0, .24);
    --primary-500: #72a0f2;
    --primary-600: #8bb4ff;
    --primary-gradient: #326fe8;
    --primary-gradient-hover: #285dcc;
}

html { background: var(--bg-primary); }
body {
    background: var(--bg-primary);
    color: var(--text-primary);
    letter-spacing: .005em;
}

/* Keep the public pages content-led. Decorative particle and hero layers are disabled. */
.particles,
#particles-js,
.hero-bg-dark,
.hero-bg-light,
.scroll-indicator { display: none !important; }
[data-aos] { opacity: 1 !important; transform: none !important; }

.container { max-width: 1240px; padding-left: 28px; padding-right: 28px; }

/* Shared navigation: solid, quiet and easy to read when zoomed. */
.site-nav.navbar,
.site-nav.navbar.scrolled,
[data-theme="light"] .site-nav.navbar,
[data-theme="light"] .site-nav.navbar.scrolled {
    position: sticky;
    top: 0;
    height: auto;
    min-height: 68px;
    background: var(--bg-primary);
    background: color-mix(in srgb, var(--bg-primary) 94%, transparent);
    border-bottom: 1px solid var(--border-primary);
    box-shadow: 0 1px 0 rgba(28, 43, 68, .02);
    backdrop-filter: blur(10px);
}
.site-nav .nav-content { min-height: 68px; gap: 22px; }
.site-nav .logo { color: var(--text-primary); font-size: 19px; }
.site-nav .logo-stickman { color: var(--primary-500); width: 31px; height: 31px; }
.site-nav .nav-menu { gap: clamp(12px, 1.7vw, 25px); }
.site-nav .nav-link { color: var(--text-secondary); font-size: 14px; font-weight: 600; }
.site-nav .nav-link:hover,
.site-nav .nav-link.active { color: var(--text-primary); }
.site-nav .nav-link.active::after { height: 2px; background: var(--primary-500); border-radius: 0; }
.site-nav .space-nav-link { color: var(--text-primary); }
.site-nav .account-nav-link { color: var(--text-primary); border-color: var(--border-primary); border-radius: 7px; padding: 8px 12px; }
.site-nav .account-nav-link:hover,
.site-nav .account-nav-link.is-signed-in { color: var(--primary-600); border-color: var(--primary-500); background: var(--bg-secondary); }
.site-nav .dropdown-menu { border: 1px solid var(--border-primary); border-radius: 8px; box-shadow: var(--shadow-lg); }
.site-nav .theme-toggle { border-width: 1px; border-radius: 7px; width: 36px; height: 36px; }

/* Homepage: replace the previous poster-like hero with a restrained information header. */
.hero {
    min-height: 600px;
    align-items: flex-start;
    justify-content: flex-start;
    padding: 118px 0 72px;
    background: var(--bg-primary);
}
.hero .container { width: 100%; }
.hero-content { max-width: 760px; padding: 0; text-align: left; }
.hero-avatar { display: none; }
.hero-title {
    max-width: 720px;
    margin-bottom: 14px;
    color: var(--text-primary);
    font-size: clamp(36px, 5vw, 58px);
    line-height: 1.16;
    letter-spacing: -.045em;
}
.hero-title .chinese-name { color: var(--primary-500); font-weight: 800; }
.hero-slogan {
    max-width: 650px;
    margin-bottom: 28px;
    color: var(--text-secondary);
    font-size: 17px;
    line-height: 1.8;
}
.hero-cta { justify-content: flex-start; gap: 10px; margin-bottom: 0; }

/* Use small, editorial cards rather than floating AI-template tiles. */
.stats-section,
.services-section,
.achievements-section,
.contact-section,
.site-intro-section { padding: 64px 0; }
.stats-grid,
.services-grid { gap: 14px; }
.stat-card,
.service-card,
.achievement-card,
.contact-info,
.policy-preview-card,
.start-card,
.learning-hub-card,
.doc-category,
.blog-card,
.problem-card {
    border: 1px solid var(--border-primary);
    border-radius: 8px;
    box-shadow: none;
}
.stat-card:hover,
.service-card:hover,
.achievement-card:hover,
.contact-info:hover,
.policy-preview-card:hover,
.start-card:hover,
.learning-hub-card:hover,
.doc-category:hover,
.blog-card:hover,
.problem-card:hover {
    transform: translateY(-2px);
    border-color: var(--primary-300);
    box-shadow: var(--shadow-md);
}
.stat-card { padding: 22px 18px; }
.stat-icon { margin-bottom: 10px; font-size: 30px; }
.stat-number { margin-bottom: 4px; font-size: 34px; }
.stat-label { font-size: 14px; }
.section-title { margin-bottom: 12px; letter-spacing: -.025em; }
.section-subtitle { margin-bottom: 34px; font-size: 16px; line-height: 1.75; }
.service-card { padding: 24px 22px; }
.service-icon { margin-bottom: 16px; font-size: 34px; }
.service-title { margin-bottom: 8px; font-size: 19px; }
.service-desc { margin-bottom: 16px; font-size: 14px; }
.service-link { font-size: 14px; }
.achievement-card { padding: 24px; text-align: left; }

/* Buttons and form controls become rectangular, quiet and consistent. */
.btn,
.admin-button,
.admin-ghost {
    border-radius: 7px;
}
.btn { padding: 11px 18px; font-size: 14px; box-shadow: none; }
.btn::before { display: none; }
.btn-primary,
.admin-button { background: var(--primary-500); box-shadow: none; }
.btn-primary:hover,
.admin-button:hover { background: var(--primary-600); transform: translateY(-1px); box-shadow: none; }
.btn-secondary,
.admin-ghost { border: 1px solid var(--border-primary); background: var(--bg-secondary); }

input, select, textarea {
    border-radius: 7px !important;
    border-color: var(--border-primary) !important;
    background: var(--bg-secondary) !important;
    color: var(--text-primary) !important;
}
input:focus, select:focus, textarea:focus {
    border-color: var(--primary-500) !important;
    box-shadow: 0 0 0 3px rgba(50, 111, 232, .14) !important;
}

/* Status, filters and progress should read like learning data, not decorations. */
.filter-chip,
.stage-tab,
.category-tab,
.level-filter,
.tag,
.blog-category { border-radius: 6px !important; }
.progress-bar,
.progress-fill { border-radius: 4px !important; }
.policy-preview-icon { border-radius: 8px; }

/* Admin remains dense and operational while using the same visual tokens. */
.admin-main { padding-top: 44px; padding-bottom: 72px; }
.admin-head,
.admin-session,
.admin-panel,
.admin-metrics article,
.review-dialog { border-radius: 8px; box-shadow: none; border-color: var(--border-primary); }
.admin-eyebrow { color: var(--primary-500); letter-spacing: .08em; }
.admin-panel-head { border-bottom-color: var(--border-primary); }

@media (max-width: 1280px) {
    .site-nav .nav-menu { top: 68px; height: calc(100dvh - 68px); max-height: calc(100dvh - 68px); background: var(--bg-secondary); }
    .site-nav .nav-menu.active { box-shadow: var(--shadow-xl); }
}
@media (max-width: 768px) {
    .container { padding-left: 18px; padding-right: 18px; }
    .hero { min-height: 0; padding: 74px 0 56px; }
    .hero-title { font-size: clamp(34px, 11vw, 48px); }
    .hero-slogan { font-size: 15px; }
    .stats-section, .services-section, .achievements-section, .contact-section, .site-intro-section { padding: 48px 0; }
    .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 10px; }
    .services-grid { grid-template-columns: 1fr; gap: 10px; }
    .service-card { padding: 20px; }
    .section-subtitle { margin-bottom: 24px; }
}
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}

/* V4: a clearer editorial learning product surface. This remains visual-only. */
:root {
    --bg-primary: #f0f2f4;
    --bg-secondary: #ffffff;
    --bg-tertiary: #e5e9ee;
    --text-primary: #182536;
    --text-secondary: #647286;
    --text-tertiary: #8b98a8;
    --border-primary: #cfd7e1;
    --border-secondary: #b9c5d2;
    --primary-500: #2469c9;
    --primary-600: #1b56a8;
    --primary-700: #153e78;
    --accent-500: #c8752e;
    --accent-600: #a65d20;
    --shadow-sm: 0 1px 2px rgba(24, 37, 54, .04);
    --shadow-md: 0 8px 20px rgba(24, 37, 54, .06);
    --shadow-lg: 0 14px 30px rgba(24, 37, 54, .08);
}

[data-theme="dark"] {
    --bg-primary: #10151c;
    --bg-secondary: #171e27;
    --bg-tertiary: #202a35;
    --text-primary: #f1f4f7;
    --text-secondary: #aab5c2;
    --text-tertiary: #7c8997;
    --border-primary: #303b48;
    --border-secondary: #435162;
    --primary-500: #72a1e5;
    --primary-600: #8bb5f1;
    --primary-700: #b5ceef;
    --accent-500: #dfa06a;
    --accent-600: #efb47d;
}

body {
    font-family: "Microsoft YaHei", "PingFang SC", "Segoe UI", Arial, sans-serif;
    background: var(--bg-primary) !important;
}

/* A solid product header replaces the floating glass/gradient treatment. */
.site-nav.navbar,
.site-nav.navbar.scrolled,
[data-theme="light"] .site-nav.navbar,
[data-theme="light"] .site-nav.navbar.scrolled,
[data-theme="dark"] .site-nav.navbar,
[data-theme="dark"] .site-nav.navbar.scrolled {
    position: sticky;
    background: var(--bg-secondary) !important;
    border-top: 3px solid var(--primary-500);
    border-bottom: 1px solid var(--border-primary);
    box-shadow: none !important;
    backdrop-filter: none;
}
.site-nav .nav-content { min-height: 66px; }
.site-nav .logo-text { letter-spacing: .02em; }
.site-nav .nav-link { letter-spacing: .015em; }
.site-nav .account-nav-link {
    background: var(--primary-500);
    color: #fff !important;
    border-color: var(--primary-500);
    box-shadow: 0 1px 2px rgba(20, 45, 70, .16);
}
.site-nav .account-nav-link:hover {
    background: var(--primary-600);
    color: #fff !important;
    border-color: var(--primary-600);
}
.site-nav .account-nav-link.is-signed-in {
    background: transparent;
    color: var(--text-primary) !important;
    border-color: var(--border-primary);
    box-shadow: none;
}
[data-theme="light"] .site-nav .nav-link.account-nav-link,
[data-theme="light"] .site-nav .nav-link.account-nav-link.active,
[data-theme="light"] .site-nav .nav-link.account-nav-link:hover {
    color: #fff !important;
}
[data-theme="light"] .site-nav .nav-link.account-nav-link.is-signed-in,
[data-theme="light"] .site-nav .nav-link.account-nav-link.is-signed-in.active,
[data-theme="light"] .site-nav .nav-link.account-nav-link.is-signed-in:hover {
    color: var(--text-primary) !important;
}

/* Homepage is now an information page, not a poster-like hero. */
.hero {
    min-height: auto;
    padding: 104px 0 88px;
    background: var(--bg-secondary) !important;
    border-bottom: 1px solid var(--border-primary);
}
.hero-content { max-width: 1240px; }
.hero-title {
    max-width: 820px;
    margin-bottom: 18px;
    font-size: clamp(42px, 6vw, 76px);
    letter-spacing: -.065em;
}
.hero-title::before {
    content: "STICKMAN / INFORMATICS";
    display: block;
    margin-bottom: 18px;
    color: var(--primary-500);
    font-size: 12px;
    font-weight: 700;
    letter-spacing: .2em;
}
.hero-slogan { max-width: 700px; font-size: 18px; }
.hero-cta .btn { min-width: 148px; text-align: center; }

.stats-section {
    padding: 36px 0;
    background: var(--bg-primary) !important;
}
.stat-card {
    display: grid;
    grid-template-columns: auto 1fr;
    grid-template-rows: auto auto;
    column-gap: 12px;
    align-items: baseline;
    padding: 18px 18px 18px 16px;
    background: var(--bg-secondary) !important;
    border: 0;
    border-left: 3px solid var(--primary-500);
    border-radius: 0;
}
.stat-icon { grid-row: 1 / span 2; margin: 0; font-size: 22px; filter: grayscale(.35); }
.stat-number { margin: 0; font-size: 28px; }
.stat-label { margin: 0; }

.services-section,
.achievements-section,
.contact-section,
.site-intro-section {
    background: var(--bg-secondary) !important;
    border-top: 1px solid var(--border-primary);
}
.section-title { font-size: clamp(25px, 3vw, 36px); }
.section-subtitle { color: var(--text-secondary); }
.services-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 0 28px; }
.service-card {
    min-height: 176px;
    padding: 24px 8px 24px 0;
    background: transparent !important;
    border: 0;
    border-top: 1px solid var(--border-primary);
    border-radius: 0;
    box-shadow: none !important;
}
.service-card:hover {
    transform: none;
    border-color: var(--primary-500);
    box-shadow: none !important;
}
.service-icon { font-size: 26px; }
.service-title { font-size: 18px; }
.service-desc { color: var(--text-secondary); }

/* Replace internal English labels in the topic-bank interface with task labels. */
.problem-bank-section .problem-heading .eyebrow,
.problem-bank-section .taxonomy-heading .eyebrow,
.problem-bank-section .problem-results-head .eyebrow { font-size: 0; }
.problem-bank-section .problem-heading .eyebrow::after,
.problem-bank-section .taxonomy-heading .eyebrow::after,
.problem-bank-section .problem-results-head .eyebrow::after {
    font-size: 12px;
    letter-spacing: .08em;
}
.problem-bank-section .problem-heading .eyebrow::after { content: "题目筛选"; }
.problem-bank-section .taxonomy-heading .eyebrow::after { content: "知识点"; }
.problem-bank-section .problem-results-head .eyebrow::after { content: "题目列表"; }

/* Shared interior pages use restrained content panels instead of floating tiles. */
.page-header,
.page-hero,
.article-hero,
.learning-hero,
.content-section,
.article-section,
.service-detail-section,
.roadmap-section,
.faq-section,
.about-section,
.experience-section,
.philosophy-section {
    background: var(--bg-primary) !important;
}
.service-detail-card,
.roadmap-card,
.philosophy-card,
.article-card,
.article-content,
.faq-item,
.guide-note,
.content-card {
    border-radius: 8px !important;
    border: 1px solid var(--border-primary) !important;
    box-shadow: none !important;
}

@media (max-width: 768px) {
    .hero { padding: 76px 0 64px; }
    .hero-title { font-size: clamp(38px, 12vw, 58px); }
    .hero-title::before { margin-bottom: 14px; font-size: 10px; }
    .services-grid { grid-template-columns: 1fr; gap: 0; }
    .service-card { min-height: 0; }
}