/* ============================================================
   账无忧 (ArcDebt) — Unified Design System v2.0
   Shared tokens for landing page, app, and legal pages.
   ============================================================ */

:root {
  /* === Brand Colors === */
  --color-primary: #1B5E4B;
  --color-primary-dark: #134A3B;
  --color-primary-light: #2D8B70;
  --color-primary-grad: linear-gradient(135deg, #1B5E4B 0%, #2D8B70 100%);
  --color-primary-bg: #F0F7F4;

  /* === Semantic Colors === */
  --color-danger: #DC2626;
  --color-danger-light: #FEF2F2;
  --color-danger-grad: linear-gradient(135deg, #DC2626 0%, #F97316 100%);

  --color-warning: #F59E0B;
  --color-warning-light: #FFFBEB;
  --color-warning-grad: linear-gradient(135deg, #F59E0B 0%, #FBBF24 100%);

  --color-success: #10B981;
  --color-success-light: #ECFDF5;
  --color-success-grad: linear-gradient(135deg, #10B981 0%, #34D399 100%);

  --color-info: #3B82F6;
  --color-info-light: #EFF6FF;
  --color-info-grad: linear-gradient(135deg, #3B82F6 0%, #60A5FA 100%);

  /* === Neutrals === */
  --gray-50:  #F8FAFC;
  --gray-100: #F1F5F9;
  --gray-200: #E2E8F0;
  --gray-300: #CBD5E1;
  --gray-400: #94A3B8;
  --gray-500: #64748B;
  --gray-600: #475569;
  --gray-700: #334155;
  --gray-800: #1E293B;
  --gray-900: #0F172A;

  --color-text-main:  var(--gray-800);
  --color-text-sub:   var(--gray-500);
  --color-text-muted: var(--gray-400);
  --color-divider:    var(--gray-200);
  --color-bg-white:   #FFFFFF;
  --color-bg-page:    var(--gray-50);

  /* === Spacing & Sizing === */
  --radius-sm:  8px;
  --radius-md:  12px;
  --radius-lg:  16px;
  --radius-xl:  20px;

  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 2px 12px rgba(0,0,0,0.06);
  --shadow-lg: 0 4px 20px rgba(0,0,0,0.10);
  --shadow-xl: 0 8px 32px rgba(0,0,0,0.12);

  --max-width: 1200px;
  --section-padding: 80px 0;

  /* === Typography === */
  --font-cn: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --font-en: "Inter", "SF Pro Display", sans-serif;
  --font-num: "DIN Alternate", "DIN", "Inter", monospace;
  --font-system: -apple-system, BlinkMacSystemFont, "Segoe UI", var(--font-cn);

  /* === Transitions === */
  --transition-fast: all 0.15s ease;
  --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============================================================
   Dark Mode
   ============================================================ */
@media (prefers-color-scheme: dark) {
  :root {
    --color-primary: #34D399;
    --color-primary-dark: #10B981;
    --color-primary-light: #6EE7B7;
    --color-primary-grad: linear-gradient(135deg, #059669 0%, #34D399 100%);
    --color-primary-bg: #0F2A24;

    --color-danger: #F87171;
    --color-danger-light: #3B1212;
    --color-warning: #FBBF24;
    --color-warning-light: #382B0A;
    --color-success: #34D399;
    --color-success-light: #0C2E22;
    --color-info: #60A5FA;
    --color-info-light: #0F2238;

    --gray-50:  #1E293B;
    --gray-100: #273449;
    --gray-200: #334155;
    --gray-300: #475569;
    --gray-400: #64748B;
    --gray-500: #94A3B8;
    --gray-600: #CBD5E1;
    --gray-700: #E2E8F0;
    --gray-800: #F1F5F9;
    --gray-900: #F8FAFC;

    --color-text-main:  var(--gray-800);
    --color-text-sub:   var(--gray-500);
    --color-text-muted: var(--gray-400);
    --color-divider:    var(--gray-200);
    --color-bg-white:   #1E293B;
    --color-bg-page:    #0F172A;

    --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
    --shadow-md: 0 2px 12px rgba(0,0,0,0.4);
    --shadow-lg: 0 4px 20px rgba(0,0,0,0.5);
    --shadow-xl: 0 8px 32px rgba(0,0,0,0.6);
  }

  /* Invert brightness of images/illustrations */
  img:not([src*=".svg"]) { filter: brightness(0.9); }
}

/* Allow manual dark mode toggle regardless of system preference */
[data-theme="dark"] {
  color-scheme: dark;
}
[data-theme="dark"] {
  --color-primary: #34D399;
  --color-primary-dark: #10B981;
  --color-primary-light: #6EE7B7;
  --color-primary-grad: linear-gradient(135deg, #059669 0%, #34D399 100%);
  --color-primary-bg: #0F2A24;

  --color-danger: #F87171;
  --color-danger-light: #3B1212;
  --color-warning: #FBBF24;
  --color-warning-light: #382B0A;
  --color-success: #34D399;
  --color-success-light: #0C2E22;
  --color-info: #60A5FA;
  --color-info-light: #0F2238;

  --gray-50:  #1E293B;
  --gray-100: #273449;
  --gray-200: #334155;
  --gray-300: #475569;
  --gray-400: #64748B;
  --gray-500: #94A3B8;
  --gray-600: #CBD5E1;
  --gray-700: #E2E8F0;
  --gray-800: #F1F5F9;
  --gray-900: #F8FAFC;

  --color-text-main:  var(--gray-800);
  --color-text-sub:   var(--gray-500);
  --color-text-muted: var(--gray-400);
  --color-divider:    var(--gray-200);
  --color-bg-white:   #1E293B;
  --color-bg-page:    #0F172A;

  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 2px 12px rgba(0,0,0,0.4);
  --shadow-lg: 0 4px 20px rgba(0,0,0,0.5);
  --shadow-xl: 0 8px 32px rgba(0,0,0,0.6);
}

/* ============================================================
   Base Reset
   ============================================================ */
* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-cn);
  color: var(--color-text-main);
  background: var(--color-bg-white);
  line-height: 1.6;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ============================================================
   Utility Classes
   ============================================================ */
.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

/* ============================================================
   Buttons
   ============================================================ */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: 8px; padding: 10px 24px; border-radius: var(--radius-sm);
  font-size: 14px; font-weight: 600; border: none; cursor: pointer;
  transition: var(--transition); white-space: nowrap;
  font-family: inherit; letter-spacing: 0.3px;
}
.btn:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; }

.btn-primary {
  background: var(--color-primary-grad); color: #fff;
  box-shadow: 0 2px 8px rgba(27,94,75,0.3);
}
.btn-primary:hover { transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(27,94,75,0.4); }

.btn-outline {
  background: transparent; color: var(--color-primary);
  border: 1.5px solid var(--color-primary);
}
.btn-outline:hover { background: var(--color-primary-bg); }

.btn-danger {
  background: var(--color-danger-grad); color: #fff;
  box-shadow: 0 2px 8px rgba(220,38,38,0.3);
}

.btn-success {
  background: var(--color-success-grad); color: #fff;
  box-shadow: 0 2px 8px rgba(16,185,129,0.3);
}

.btn-sm { padding: 5px 12px; font-size: 12px; }
.btn-lg { padding: 14px 32px; font-size: 16px; }

/* ============================================================
   Tags / Badges
   ============================================================ */
.tag {
  display: inline-flex; align-items: center;
  padding: 3px 10px; border-radius: 6px;
  font-size: 11px; font-weight: 600; letter-spacing: 0.3px;
}
.tag-red    { background: var(--color-danger-light); color: var(--color-danger); }
.tag-amber  { background: var(--color-warning-light); color: #B45309; }
.tag-green  { background: var(--color-success-light); color: var(--color-success); }
.tag-purple { background: var(--color-primary-bg); color: var(--color-primary); }
.tag-gray   { background: var(--gray-100); color: var(--gray-500); }
.tag-blue   { background: var(--color-info-light); color: var(--color-info); }

/* ============================================================
   Cards
   ============================================================ */
.card {
  background: var(--color-bg-white);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-divider);
  transition: var(--transition);
}
.card:hover { box-shadow: var(--shadow-md); }

.card-header {
  padding: 16px 24px; border-bottom: 1px solid var(--color-divider);
  font-size: 14px; font-weight: 700; color: var(--color-text-main);
  display: flex; align-items: center; gap: 10px;
}
.card-header::before {
  content: ''; width: 3px; height: 16px; border-radius: 2px;
  background: var(--color-primary-grad); flex-shrink: 0;
}
.card-body { padding: 20px 24px; }

/* ============================================================
   Forms
   ============================================================ */
.form-group { margin-bottom: 18px; }
.form-group label {
  display: block; font-size: 13px; font-weight: 600;
  color: var(--color-text-sub); margin-bottom: 6px;
}
.form-group input,
.form-group select,
.form-group textarea {
  width: 100%; padding: 10px 14px;
  border: 1.5px solid var(--color-divider);
  border-radius: var(--radius-sm); font-size: 14px;
  outline: none; transition: var(--transition-fast);
  font-family: inherit; background: var(--color-bg-white);
  color: var(--color-text-main);
}
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-bg);
}
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.form-row-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 18px; }

/* ============================================================
   Scrollbar
   ============================================================ */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--gray-300); border-radius: 6px; }
::-webkit-scrollbar-thumb:hover { background: var(--gray-400); }

/* ============================================================
   Animations
   ============================================================ */
@keyframes fadeIn   { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideUp  { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: translateY(0); } }
@keyframes slideDown{ from { opacity: 0; transform: translateY(-12px); } to { opacity: 1; transform: translateY(0); } }
@keyframes pulse    { 0%, 100% { opacity: 1; } 50% { opacity: 0.6; } }
.animate-fade-in  { animation: fadeIn 0.3s ease; }
.animate-slide-up { animation: slideUp 0.35s cubic-bezier(0.4,0,0.2,1); }
.animate-pulse    { animation: pulse 2s infinite; }

/* ============================================================
   Responsive
   ============================================================ */
@media (max-width: 768px) {
  :root { --section-padding: 48px 0; }
  .form-row, .form-row-3 { grid-template-columns: 1fr; }
  .container { padding: 0 16px; }
}