/* ==========================================================================
   THEME DEFINITIONS (UAA-CALIBRATED SEAMLESS READING PALETTES)
   ========================================================================== */

/* 1. Theme: Warm Rice Paper (复古米黄 / 羊皮纸) */
html.theme-paper, body.theme-paper {
  --bg-app: #f4ecd8;
  --bg-surface: #faf4e6;
  --bg-surface-elevated: #eae0c7;
  --bg-surface-hover: #dfd4b8;
  
  --border-subtle: #e6dcc4;
  --border-medium: #d4c7a6;
  --border-focus: #b45309;

  --text-primary: #2d2419;
  --text-secondary: #5c4e3c;
  --text-muted: #8c7c67;
  
  --accent-gold: #b45309;
  --accent-gold-hover: #92400e;
  --accent-gold-subtle: rgba(180, 83, 9, 0.12);
  --accent-gold-border: rgba(180, 83, 9, 0.35);

  --reader-bg: #f4ecd8;
  --reader-text: #261e14;
  --reader-secondary: #6e5e49;

  --rchrome-bg: rgba(244, 236, 216, 0.88);
  --rchrome-solid: #f4ecd8;
  --rchrome-ink: #261e14;
  --rchrome-ink-2: #4a3d2c;
  --rchrome-mut: #82725e;
  --rchrome-line: rgba(180, 140, 90, 0.22);
  --rchrome-fill: rgba(0, 0, 0, 0.05);
  --rchrome-fill-2: rgba(0, 0, 0, 0.09);
  
  --cover-gradient-top: #eae0c7;
  --cover-gradient-bot: #f4ecd8;
}

/* 2. Theme: Bamboo Sage (青竹护眼绿) */
html.theme-sage, body.theme-sage {
  --bg-app: #dde8d9;
  --bg-surface: #e9f2e6;
  --bg-surface-elevated: #d1ded0;
  --bg-surface-hover: #c4d4c2;
  
  --border-subtle: #cbd7c5;
  --border-medium: #b5c6af;
  --border-focus: #166534;

  --text-primary: #1e291c;
  --text-secondary: #3d4f3b;
  --text-muted: #6b7f68;
  
  --accent-gold: #166534;
  --accent-gold-hover: #14532d;
  --accent-gold-subtle: rgba(22, 101, 52, 0.14);
  --accent-gold-border: rgba(22, 101, 52, 0.35);

  --reader-bg: #dde8d9;
  --reader-text: #1a2419;
  --reader-secondary: #475a45;

  --rchrome-bg: rgba(221, 232, 217, 0.88);
  --rchrome-solid: #dde8d9;
  --rchrome-ink: #1a2419;
  --rchrome-ink-2: #384936;
  --rchrome-mut: #687c66;
  --rchrome-line: rgba(70, 110, 65, 0.22);
  --rchrome-fill: rgba(0, 0, 0, 0.05);
  --rchrome-fill-2: rgba(0, 0, 0, 0.09);

  --cover-gradient-top: #d1ded0;
  --cover-gradient-bot: #dde8d9;
}

/* 3. Theme: Polar Light (雅致暖白) */
html.theme-light, body.theme-light {
  --bg-app: #fbfaf7;
  --bg-surface: #ffffff;
  --bg-surface-elevated: #f3f2ee;
  --bg-surface-hover: #e8e6e0;
  
  --border-subtle: #ececf0;
  --border-medium: #dad8d2;
  --border-focus: #0284c7;

  --text-primary: #18181b;
  --text-secondary: #3f3f46;
  --text-muted: #71717a;
  
  --accent-gold: #0284c7;
  --accent-gold-hover: #0369a1;
  --accent-gold-subtle: rgba(2, 132, 199, 0.12);
  --accent-gold-border: rgba(2, 132, 199, 0.35);

  --reader-bg: #fbfaf7;
  --reader-text: #18181b;
  --reader-secondary: #3f3f46;

  --rchrome-bg: rgba(251, 250, 247, 0.9);
  --rchrome-solid: #fbfaf7;
  --rchrome-ink: #18181b;
  --rchrome-ink-2: #3f3f46;
  --rchrome-mut: #71717a;
  --rchrome-line: rgba(0, 0, 0, 0.12);
  --rchrome-fill: rgba(0, 0, 0, 0.05);
  --rchrome-fill-2: rgba(0, 0, 0, 0.09);

  --cover-gradient-top: #f3f2ee;
  --cover-gradient-bot: #ffffff;
}

/* 4. Theme: Deep Ink (深蓝墨夜 - UAA 独家夜读) */
html.theme-ink, body.theme-ink {
  --bg-app: #101226;
  --bg-surface: #171a35;
  --bg-surface-elevated: #202449;
  --bg-surface-hover: #2b305e;
  
  --border-subtle: #23253f;
  --border-medium: #35395f;
  --border-focus: #818cf8;

  --text-primary: #f0f2fa;
  --text-secondary: #b8bee3;
  --text-muted: #8b92bf;
  
  --accent-gold: #818cf8;
  --accent-gold-hover: #a5b4fc;
  --accent-gold-subtle: rgba(129, 140, 248, 0.18);
  --accent-gold-border: rgba(129, 140, 248, 0.4);

  --reader-bg: #101226;
  --reader-text: #e2e5f5;
  --reader-secondary: #9da3cd;

  --rchrome-bg: rgba(16, 18, 38, 0.88);
  --rchrome-solid: #101226;
  --rchrome-ink: #f0f2fa;
  --rchrome-ink-2: #c6cae6;
  --rchrome-mut: #8b92bf;
  --rchrome-line: rgba(255, 255, 255, 0.12);
  --rchrome-fill: rgba(255, 255, 255, 0.08);
  --rchrome-fill-2: rgba(255, 255, 255, 0.14);

  --cover-gradient-top: #202449;
  --cover-gradient-bot: #101226;
}

/* 5. Theme: Obsidian Night (暗夜纯黑 - 100% 还原 iOS 原生深色风格) */
html.theme-obsidian, body.theme-obsidian {
  --bg-app: #000000;
  --bg-surface: #121214;
  --bg-surface-elevated: #1c1c1e;
  --bg-surface-hover: #2c2c2e;
  
  --border-subtle: #242426;
  --border-medium: #38383a;
  --border-focus: #e5a93c;

  --text-primary: #f5f5f7;
  --text-secondary: #aeaeb2;
  --text-muted: #8e8e93;
  
  --accent-gold: #d49a37;
  --accent-gold-hover: #e5a93c;
  --accent-gold-subtle: rgba(212, 154, 55, 0.16);
  --accent-gold-border: rgba(212, 154, 55, 0.35);

  --reader-bg: #000000;
  --reader-text: #e5e5ea;
  --reader-secondary: #8e8e93;

  --rchrome-bg: rgba(18, 18, 20, 0.88);
  --rchrome-solid: #121214;
  --rchrome-ink: #f5f5f7;
  --rchrome-ink-2: #c7c7cc;
  --rchrome-mut: #8e8e93;
  --rchrome-line: rgba(255, 255, 255, 0.12);
  --rchrome-fill: rgba(255, 255, 255, 0.08);
  --rchrome-fill-2: rgba(255, 255, 255, 0.14);

  --cover-gradient-top: #1c1c1e;
  --cover-gradient-bot: #000000;
}