/* /static/css/design-system.css */
/* Tianyu Design System — Kimi-inspired dark glass + tokenized chrome */

/* ========== 0) Design Tokens ========== */
:root {
  color-scheme: dark light;

  /* --- Accent / Brand --- */
  --ty-accent: #8b5cf6;     /* purple */
  --ty-accent-2: #38bdf8;   /* sky */
  --ty-accent-3: #2563eb;   /* blue */

  /* --- Default: DARK scheme (align with Kimi) --- */
  --ty-bg: #050814;
  --ty-bg-soft: rgba(255, 255, 255, 0.04);
  --ty-surface: rgba(255, 255, 255, 0.06);     /* glass surface */
  --ty-surface-2: rgba(255, 255, 255, 0.09);   /* hover surface */
  --ty-border: rgba(255, 255, 255, 0.10);

  --ty-text: rgba(255, 255, 255, 0.92);
  --ty-text-muted: rgba(255, 255, 255, 0.68);
  --ty-link: rgba(255, 255, 255, 0.92);

  /* --- Tokenized "chrome" backgrounds (header/footer) --- */
  --ty-chrome-bg: rgba(8, 10, 22, 0.65);
  --ty-chrome-bg-blur: rgba(8, 10, 22, 0.45);

  /* --- Dropdown menu background --- */
  --ty-menu-bg: rgba(12, 14, 28, 0.72);
  --ty-menu-bg-blur: rgba(12, 14, 28, 0.52);

  /* Typography */
  --ty-font-sans: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto,
                  "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
                  "Helvetica Neue", Arial, "Apple Color Emoji", "Segoe UI Emoji";
  --ty-font-serif: ui-serif, "Noto Serif SC", "Source Han Serif SC", "Songti SC", serif;

  /* Type scale */
  --ty-text-sm: 0.875rem;
  --ty-text-base: 1rem;
  --ty-text-lg: 1.125rem;
  --ty-h1: 2.1rem;
  --ty-h2: 1.6rem;
  --ty-h3: 1.25rem;

  /* Spacing */
  --ty-1: 4px;
  --ty-2: 8px;
  --ty-3: 12px;
  --ty-4: 16px;
  --ty-5: 20px;
  --ty-6: 24px;
  --ty-8: 32px;
  --ty-10: 40px;
  --ty-12: 48px;

  /* Radius & shadow */
  --ty-radius: 16px;
  --ty-radius-sm: 12px;
  --ty-shadow: 0 18px 60px rgba(0,0,0,0.45);
  --ty-shadow-sm: 0 10px 30px rgba(0,0,0,0.35);

  /* Layout */
  --ty-container: 1200px;
  --ty-container-wide: 1600px;
}

/* Light preference: override tokens (including header/footer/menu backgrounds!) */
@media (prefers-color-scheme: light) {
  :root {
    --ty-bg: #f7f9ff;
    --ty-bg-soft: rgba(15, 23, 42, 0.03);
    --ty-surface: rgba(255, 255, 255, 0.78);
    --ty-surface-2: rgba(255, 255, 255, 0.92);
    --ty-border: rgba(15, 23, 42, 0.10);

    --ty-text: rgba(15, 23, 42, 0.92);
    --ty-text-muted: rgba(15, 23, 42, 0.65);
    --ty-link: rgba(15, 23, 42, 0.92);

    --ty-shadow: 0 18px 60px rgba(2,6,23,0.12);
    --ty-shadow-sm: 0 10px 30px rgba(2,6,23,0.10);

    /* ✅ Fix: chrome/menu backgrounds must also become light */
    --ty-chrome-bg: rgba(255, 255, 255, 0.78);
    --ty-chrome-bg-blur: rgba(255, 255, 255, 0.62);

    --ty-menu-bg: rgba(255, 255, 255, 0.92);
    --ty-menu-bg-blur: rgba(255, 255, 255, 0.82);
  }
}

/* ========== 1) Base styles ========== */
*, *::before, *::after { box-sizing: border-box; }

html, body { height: 100%; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--ty-font-sans);
  color: var(--ty-text);
  line-height: 1.65;
  display: flex;
  flex-direction: column;

  /* Kimi-like "space" background */
  background:
    radial-gradient(1200px 650px at 18% 18%, rgba(139,92,246,0.32), transparent 60%),
    radial-gradient(900px 520px at 82% 12%, rgba(56,189,248,0.22), transparent 55%),
    radial-gradient(720px 420px at 72% 82%, rgba(37,99,235,0.18), transparent 60%),
    linear-gradient(180deg, var(--ty-bg) 0%, rgba(5, 8, 20, 0.98) 55%, var(--ty-bg) 100%);
}

body::before{
  content:"";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: 0.14;
  background-image:
    radial-gradient(rgba(255,255,255,0.75) 1px, transparent 1.6px),
    radial-gradient(rgba(255,255,255,0.55) 1px, transparent 1.6px),
    radial-gradient(rgba(255,255,255,0.35) 1px, transparent 1.6px);
  background-size: 110px 110px, 160px 160px, 220px 220px;
  background-position: 0 0, 40px 70px, 90px 30px;
}

main { flex: 1 0 auto; padding: var(--ty-10) 0; }

a { color: var(--ty-link); text-decoration: none; }
a:hover { text-decoration: underline; }

:focus-visible{
  outline: 2px solid rgba(56,189,248,0.75);
  outline-offset: 2px;
  border-radius: 8px;
}

/* Headings */
h1 { font-size: var(--ty-h1); margin: var(--ty-8) 0 var(--ty-4); letter-spacing: -0.02em; }
h2 { font-size: var(--ty-h2); margin: var(--ty-6) 0 var(--ty-3); letter-spacing: -0.01em; }
h3 { font-size: var(--ty-h3); margin: var(--ty-5) 0 var(--ty-2); }

.container {
  max-width: var(--ty-container);
  margin: 0 auto;
  padding: 0 var(--ty-4);
}

/* ========== 2) Header / Nav ========== */
header {
  position: sticky;
  top: 0;
  z-index: 1100;

  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--ty-4);

  padding: 14px 28px;
  border-bottom: 1px solid var(--ty-border);

  /* ✅ tokenized */
  background: var(--ty-chrome-bg);
}

@supports ((-webkit-backdrop-filter: blur(10px)) or (backdrop-filter: blur(10px))) {
  header {
    -webkit-backdrop-filter: blur(12px);
    backdrop-filter: blur(12px);
    background: var(--ty-chrome-bg-blur);
  }
}

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

header img {
  height: 44px;
  width: auto;
  border-radius: 12px;
  box-shadow: var(--ty-shadow-sm);
}

.site-title {
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  user-select: none;
  margin: 0;
  line-height: 1;

  background: linear-gradient(90deg, var(--ty-accent) 0%, var(--ty-accent-2) 55%, rgba(255,255,255,0.90) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
@media (prefers-color-scheme: light) {
  .site-title{
    background: linear-gradient(90deg, #06B6D4 0%, #3B82F6 60%, #8B5CF6 100%);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    filter: drop-shadow(0 1px 1px rgba(2,6,23,0.18));
  }
}
nav > ul {
  display: flex;
  align-items: center;
  gap: 18px;
  margin: 0;
  padding: 0;
}

/* ========== 3) Dropdown: remove markers + glass menu ========== */
header nav ul,
header nav ol,
header nav li {
  list-style: none;
  margin: 0;
  padding: 0;
}
header nav li::marker { content: ""; }
header nav ul ul { list-style: none; margin: 0; padding: 0; }

nav > ul > li { position: relative; font-size: 1rem; font-weight: 500; }

nav ul li > a,
nav ul li > span {
  display: inline-flex;
  align-items: center;
  gap: 6px;

  padding: 8px 12px;
  border-radius: 10px;
  cursor: pointer;

  color: var(--ty-text);
  background: transparent;
  transition: background .16s ease, transform .16s ease, color .16s ease;
}

nav ul li > a:hover,
nav ul li > span:hover {
  background: var(--ty-bg-soft);
  text-decoration: none;
  transform: translateY(-1px);
}

nav ul li.has-sub > ul {
  display: block;
  position: absolute;
  top: calc(100% + 8px);
  left: 0;

  min-width: 220px;
  z-index: 1200;

  padding: 10px 0;
  border-radius: 14px;
  border: 1px solid var(--ty-border);
  box-shadow: var(--ty-shadow);

  background: var(--ty-menu-bg);

  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transform: translateY(8px);
  transition: opacity .15s ease, transform .15s ease, visibility 0s linear .15s;
}

@supports ((-webkit-backdrop-filter: blur(10px)) or (backdrop-filter: blur(10px))) {
  nav ul li.has-sub > ul {
    -webkit-backdrop-filter: blur(14px);
    backdrop-filter: blur(14px);
    background: var(--ty-menu-bg-blur);
  }
}

nav ul li.has-sub:hover > ul,
nav ul li.has-sub:focus-within > ul,
nav ul li.has-sub.open > ul {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: translateY(0);
  transition: opacity .15s ease, transform .15s ease, visibility 0s;
}

nav ul li ul li { padding: 0 14px; }

nav ul li ul li a {
  display: block;
  padding: 8px 10px;
  border-radius: 10px;
  color: var(--ty-text);
  text-decoration: none;
  transition: background .16s ease, transform .16s ease;
}

nav ul li ul li a:hover {
  background: var(--ty-surface-2);
  transform: translateX(2px);
}

/* ========== 4) Main content shell ========== */
.main-content {
  width: 100%;
  max-width: var(--ty-container-wide);
  margin: 0 auto;

  padding: var(--ty-10) var(--ty-10);
  border-radius: 22px;
  border: 1px solid var(--ty-border);
  background: var(--ty-surface);
  box-shadow: var(--ty-shadow);

  min-height: 60vh;
}

@supports ((-webkit-backdrop-filter: blur(10px)) or (backdrop-filter: blur(10px))) {
  .main-content {
    -webkit-backdrop-filter: blur(16px);
    backdrop-filter: blur(16px);
  }
}

/* ========== 5) Footer ========== */
footer {
  border-top: 1px solid var(--ty-border);
  background: var(--ty-chrome-bg);

  padding: 26px 0 16px 0;
  margin-top: 22px;

  color: var(--ty-text);
}

@supports ((-webkit-backdrop-filter: blur(10px)) or (backdrop-filter: blur(10px))) {
  footer {
    -webkit-backdrop-filter: blur(12px);
    backdrop-filter: blur(12px);
    background: var(--ty-chrome-bg-blur);
  }
}

.footer-content {
  width: 100%;
  max-width: var(--ty-container-wide);
  margin: 0 auto;
  padding: 0 var(--ty-10);
}

.footer-grid {
  display: grid;
  grid-template-columns: 220px 1.2fr 1fr;
  gap: 26px;
  align-items: start;
}

.footer-logo { padding-top: 4px; min-width: 160px; }
.footer-logo a { display: inline-block; text-decoration: none; }

.tdli-logo {
  display: block;
  height: 44px;
  width: auto;
  border-radius: 0;
  box-shadow: none;
}

.footer-section h3 {
  margin: 0 0 10px 0;
  font-size: 1.05rem;
  color: rgba(56,189,248,0.90);
}

.footer-section ul {
  list-style: none;
  padding: 0;
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--ty-text-muted);
}
.footer-section ul li { margin: 0 0 8px 0; }

.footer-links a { color: var(--ty-text); }
.footer-links a:hover { text-decoration: underline; }

.footer-bottom {
  margin-top: 14px;
  padding-top: 10px;
  border-top: 1px solid var(--ty-border);
  text-align: center;
}

.icp-info {
  margin: 0;
  font-size: 0.85rem;
  color: var(--ty-text-muted);
}

/* ========== 6) UI components (shared across pages) ========== */
.ty-btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap: 8px;

  padding: 10px 14px;
  border-radius: 12px;
  border: 1px solid var(--ty-border);

  color: var(--ty-text);
  background: transparent;

  text-decoration:none;
  user-select:none;

  transition: transform .16s ease, background .16s ease, border-color .16s ease, box-shadow .16s ease;
}
.ty-btn:hover{ transform: translateY(-1px); text-decoration:none; }

.ty-btn__icon{ line-height: 1; }

.ty-btn--primary{
  background: linear-gradient(90deg, rgba(139,92,246,0.95), rgba(56,189,248,0.85));
  color: rgba(255,255,255,0.95);
  border-color: rgba(255,255,255,0.18);
}
.ty-btn--primary:hover{
  box-shadow: var(--ty-shadow-sm);
}

.ty-btn--secondary{
  background: var(--ty-bg-soft);
  color: var(--ty-text);
}
.ty-btn--secondary:hover{
  background: var(--ty-surface-2);
}

.ty-btn--ghost{
  width: 100%;
  background: transparent;
  color: var(--ty-text);
}

.ty-card{
  border-radius: 16px;
  border: 1px solid var(--ty-border);
  background: var(--ty-surface);
  padding: 16px;
}

.ty-card--hover{
  transition: transform .16s ease, background .16s ease, box-shadow .16s ease;
}
.ty-card--hover:hover{
  transform: translateY(-2px);
  background: var(--ty-surface-2);
  box-shadow: var(--ty-shadow-sm);
}

.ty-metric__value{
  font-size: 1.6rem;
  font-weight: 800;
  letter-spacing: -0.01em;
}
.ty-metric__label{
  margin-top: 6px;
  color: var(--ty-text-muted);
  font-size: 0.92rem;
}

/* ========== 7) Legacy / compatibility helpers (optional, harmless) ========== */
.site-brand { display: flex; align-items: center; gap: var(--ty-3); }
.site-brand__divider { width: 1px; height: 28px; background: var(--ty-border); }
.site-logo { display: inline-flex; align-items: center; gap: var(--ty-2); }
.site-logo img { display: block; height: 28px; width: auto; }
.site-logo__title { font-weight: 600; color: var(--ty-text); white-space: nowrap; }

/* ========== 8) Reduced motion (accessibility) ========== */
@media (prefers-reduced-motion: reduce) {
  /* Minimize non-essential motion */
  .ty-btn,
  .ty-card--hover,
  nav ul li > a,
  nav ul li > span,
  nav ul li.has-sub > ul {
    transition: none !important;
  }

  .ty-btn:hover,
  .ty-card--hover:hover,
  nav ul li > a:hover,
  nav ul li > span:hover,
  nav ul li ul li a:hover {
    transform: none !important;
  }

  nav ul li.has-sub > ul {
    transform: none !important;
  }
}

/* ========== 9) Responsive ========== */
@media (max-width: 900px) {
  header { padding: 12px 12px; }
  .main-content { padding: 18px 12px; border-radius: 18px; }
  .footer-content { padding: 0 12px; }

  .footer-grid { grid-template-columns: 1fr; gap: 14px; }
  .tdli-logo { height: 42px; }
}

@media (max-width: 600px) {
  header { flex-direction: column; align-items: flex-start; gap: 10px; }
  nav > ul { gap: 10px; flex-wrap: wrap; }
  header img { height: 42px; }
  .site-title { font-size: 1.2rem; }
}