/* css/variables.css — CSS custom properties (design tokens).
   Load FIRST. All theme colors, spacing, typography defined here. */

:root{--green-rgb:88,204,2;--blue-rgb:28,176,246;--green:#58CC02;--green-dark:#46A302;--green-light:#E8F8E0;--blue:#1CB0F6;--blue-dark:#1899D6;--blue-light:#E0F4FF;--orange:#FF9600;--orange-dark:#E08600;--red:#FF6B7A;--purple:#CE82FF;--purple-light:#F3E8FF;--bg:#F7F7F7;--card:#FFFFFF;--text:#3C3C3C;--text-light:#777;--text-lighter:#AFAFAF;--border:#E5E5E5;--shadow:0 2px 12px rgba(0,0,0,0.08);--shadow-md:0 4px 16px rgba(0,0,0,0.1);--shadow-lg:0 8px 32px rgba(0,0,0,0.12);--shadow-xl:0 12px 48px rgba(0,0,0,0.15);--shadow-green:0 4px 16px rgba(88,204,2,0.25);--shadow-blue:0 4px 16px rgba(28,176,246,0.2);--radius:16px;--radius-sm:10px;--radius-xs:8px;--radius-lg:20px;--radius-xl:24px;--section-bg:#FAFAFA;--hover-bg:#F0FFF0;--correct-bg:#E5F8D0;--wrong-bg:#FFE5E5;--calc-num-bg:#fff;--calc-op-bg:#F0F0F0;--calc-sci-bg:#F8F0FF;--flashcard-grad-start:#E8F8E0;--flashcard-grad-end:#E0F0FF;--settings-overlay-bg:rgba(0,0,0,0.5);--hero-grad-start:#4FC3F7;--hero-grad-end:#2196F3;--hero-text:#fff;--hero-pos-bg:rgba(255,255,255,0.2);--hero-btn-bg:rgba(255,255,255,0.2);--hero-btn-hover:rgba(255,255,255,0.35);--font:-apple-system,BlinkMacSystemFont,'Segoe UI','PingFang SC','Microsoft YaHei',sans-serif;--nav-height:60px;--header-height:52px;--transition-fast:0.15s ease;--transition-normal:0.25s cubic-bezier(0.4,0,0.2,1);--transition-smooth:0.35s cubic-bezier(0.4,0,0.2,1);--font-display:'Baloo 2','Arial Rounded MT Bold','Trebuchet MS','PingFang SC','Microsoft YaHei',sans-serif}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}