/* ============================================
   优学仕教育官网 · Base（排版 / 栅格 / 工具类）
   ============================================ */
html {
  font-family: var(--font-cn);
  font-size: 16px;
  line-height: 1.7;
  color: var(--ink-700);
  background: var(--bg);
}

body {
  font-family: var(--font-cn);
  color: var(--ink-700);
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  color: var(--ink-900);
  line-height: 1.3;
  font-weight: 700;
  letter-spacing: -0.01em;
}

p { line-height: 1.8; }

strong { color: var(--ink-900); font-weight: 600; }

/* ---------- 容器 ---------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding-left: var(--container-pad);
  padding-right: var(--container-pad);
}

/* ---------- 区块通用 ---------- */
.section {
  position: relative;
  padding-top: var(--section-pad);
  padding-bottom: var(--section-pad);
}

.section--soft { background: var(--bg-soft); }
.section--deep  { background: var(--bg-deep); }
.section--white { background: var(--bg); }
.section--dark  { background: var(--grad-deep); color: rgba(255,255,255,0.82); }

.section-head {
  max-width: 760px;
  margin-bottom: clamp(36px, 5vw, 60px);
}

.section-head--center {
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}

.section-head__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--purple-500);
  background: var(--purple-100);
  padding: 6px 16px;
  border-radius: var(--radius-full);
  margin-bottom: 18px;
}

.section-head__eyebrow::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--purple-500);
}

.section-head__eyebrow--gold {
  color: var(--gold-500);
  background: var(--gold-100);
}
.section-head__eyebrow--gold::before { background: var(--gold-500); }

.section-head h2 {
  font-size: var(--fs-h2);
  margin-bottom: 14px;
}

.section-head__desc {
  color: var(--ink-500);
  font-size: var(--fs-body);
  max-width: 620px;
}

.section-head--center .section-head__desc { margin: 0 auto; }

.section--dark .section-head__eyebrow {
  color: var(--purple-300);
  background: rgba(139, 60, 246, 0.18);
}
.section--dark .section-head h2 { color: #ffffff; }
.section--dark .section-head__desc { color: rgba(255,255,255,0.72); }

/* ---------- 网格 ---------- */
.grid {
  display: grid;
  gap: 24px;
}
.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }

/* ---------- 文本工具 ---------- */
.text-gradient {
  background: var(--grad-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

.text-gold {
  color: var(--gold-500);
}

.text-center { text-align: center; }

/* ---------- 数据数字 ---------- */
.num {
  font-family: var(--font-en);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

/* ---------- 通用按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 30px;
  border-radius: var(--radius-md);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.02em;
  line-height: 1;
  transition: all var(--dur) var(--ease);
  white-space: nowrap;
  user-select: none;
  position: relative;
  overflow: hidden;
}

.btn--md { padding: 11px 22px; font-size: 14px; }
.btn--lg { padding: 17px 40px; font-size: 16px; }
.btn--block { width: 100%; }

/* 主按钮：品牌紫 */
.btn--primary {
  color: #ffffff;
  background: var(--grad-brand);
  box-shadow: var(--shadow-purple);
}
.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 16px 40px rgba(139, 60, 246, 0.42);
}
.btn--primary:active { transform: translateY(0); }
.btn--primary.is-loading {
  color: transparent;
  pointer-events: none;
}
.btn--primary.is-loading::after {
  content: "";
  position: absolute;
  width: 18px;
  height: 18px;
  border: 2px solid rgba(255,255,255,0.35);
  border-top-color: #ffffff;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

/* 金色行动按钮 */
.btn--gold {
  color: #3d2a05;
  background: var(--grad-gold);
  box-shadow: var(--shadow-gold);
}
.btn--gold:hover {
  transform: translateY(-2px);
  box-shadow: 0 18px 42px rgba(245, 182, 66, 0.45);
}

/* 描边按钮 */
.btn--outline {
  color: var(--purple-600);
  border: 1.5px solid var(--purple-300);
  background: transparent;
}
.btn--outline:hover {
  border-color: var(--purple-500);
  color: var(--purple-500);
  background: var(--purple-50);
}

/* 白色按钮（深色背景上） */
.btn--white {
  color: var(--purple-700);
  background: #ffffff;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.18);
}
.btn--white:hover { transform: translateY(-2px); box-shadow: 0 16px 40px rgba(0,0,0,0.26); }

/* 幽灵按钮（深色背景） */
.btn--ghost {
  color: #ffffff;
  border: 1.5px solid rgba(255,255,255,0.45);
  background: rgba(255,255,255,0.06);
  backdrop-filter: blur(4px);
}
.btn--ghost:hover { background: rgba(255,255,255,0.14); border-color: rgba(255,255,255,0.7); }

.btn:disabled { opacity: 0.55; cursor: not-allowed; transform: none !important; }

/* ---------- 链接按钮 ---------- */
.link-more {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  font-weight: 600;
  color: var(--purple-500);
  transition: gap var(--dur) var(--ease);
}
.link-more:hover { gap: 11px; color: var(--purple-700); }
.link-more .arrow { transition: transform var(--dur) var(--ease); }

/* ---------- 标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 4px 12px;
  border-radius: var(--radius-full);
  font-size: 12.5px;
  font-weight: 500;
  line-height: 1.6;
  background: var(--purple-100);
  color: var(--purple-700);
}
.tag--gold { background: var(--gold-100); color: #9a6a00; }
.tag--soft { background: var(--bg-soft); color: var(--ink-500); border: 1px solid var(--line); }
.tag--outline { background: transparent; border: 1px solid var(--purple-300); color: var(--purple-600); }

/* ---------- 卡片 ---------- */
.card {
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: all var(--dur) var(--ease);
}
.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--purple-200);
}

/* ---------- 表单 ---------- */
.field { margin-bottom: 20px; }

.field__label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  color: var(--ink-700);
  margin-bottom: 8px;
}
.field__label .req { color: var(--danger); margin-left: 2px; }

.field__input {
  width: 100%;
  padding: 13px 16px;
  border: 1.5px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--bg);
  font-size: 15px;
  color: var(--ink-900);
  transition: all var(--dur) var(--ease);
}
.field__input::placeholder { color: var(--ink-400); }
.field__input:focus {
  border-color: var(--purple-500);
  box-shadow: 0 0 0 4px rgba(139, 60, 246, 0.12);
}
.field__input.is-error { border-color: var(--danger); }

.field__msg {
  display: none;
  font-size: 12.5px;
  color: var(--danger);
  margin-top: 6px;
}
.field__msg.is-visible { display: block; }

select.field__input {
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='14' height='14' viewBox='0 0 24 24' fill='none' stroke='%236b6680' stroke-width='2.4' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  padding-right: 42px;
  cursor: pointer;
}

/* ---------- 滚动入场动效 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
  will-change: opacity, transform;
}
.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}
.reveal-delay-1 { transition-delay: 0.08s; }
.reveal-delay-2 { transition-delay: 0.16s; }
.reveal-delay-3 { transition-delay: 0.24s; }
.reveal-delay-4 { transition-delay: 0.32s; }

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}

/* ---------- 关键帧 ---------- */
@keyframes spin { to { transform: rotate(360deg); } }

@keyframes floatY {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-16px); }
}

@keyframes floatY-slow {
  0%, 100% { transform: translateY(0) scale(1); }
  50% { transform: translateY(-22px) scale(1.04); }
}

@keyframes pulse-glow {
  0%, 100% { opacity: 0.5; }
  50% { opacity: 1; }
}

@keyframes scrollDot {
  0% { transform: translateY(0); opacity: 1; }
  70% { transform: translateY(16px); opacity: 0; }
  100% { transform: translateY(0); opacity: 0; }
}

@keyframes marquee {
  from { transform: translateX(0); }
  to { transform: translateX(-50%); }
}

@keyframes shine {
  from { transform: translateX(-120%) skewX(-18deg); }
  to { transform: translateX(220%) skewX(-18deg); }
}

/* 无障碍 */
.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;
}