:root {
  --ink: #1d3557;
  --muted: #60789c;
  --sky: #bde8ff;
  --card: #ffffff;
  --math: #d7f5e9;
  --math-shadow: #9adfc2;
  --chinese: #ffe3e3;
  --chinese-shadow: #f5b5b5;
  --english: #ebe3ff;
  --english-shadow: #c9b8f0;
  --sun: #ffd23f;
}

* {
  box-sizing: border-box;
  -webkit-tap-highlight-color: transparent;
}

html,
body {
  margin: 0;
  min-height: 100%;
}

body {
  min-height: 100vh;
  padding: 20px;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 16%, rgba(255, 255, 255, .75) 0 38px, transparent 39px),
    radial-gradient(circle at 86% 12%, rgba(255, 255, 255, .65) 0 52px, transparent 53px),
    radial-gradient(circle at 72% 88%, rgba(255, 255, 255, .55) 0 44px, transparent 45px),
    var(--sky);
  font-family: "PingFang SC", "PingFang TC", "Microsoft YaHei", system-ui, sans-serif;
}

.portal,
.placeholder-page {
  width: min(100%, 760px);
  margin: 0 auto;
}

.hero {
  margin: 18px 0 28px;
  text-align: center;
}

.hero-emoji {
  margin-bottom: 4px;
  font-size: 3.6rem;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: .78rem;
  font-weight: 800;
  letter-spacing: .13em;
}

h1 {
  margin: 0;
  font-size: clamp(2rem, 7vw, 3rem);
}

.subtitle {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 1.05rem;
  font-weight: 600;
}

.subject-grid {
  display: grid;
  gap: 18px;
}

.subject-card {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 18px;
  align-items: center;
  min-height: 132px;
  padding: 22px;
  border: 3px solid rgba(255, 255, 255, .8);
  border-radius: 26px;
  color: var(--ink);
  text-decoration: none;
  transition: transform .15s ease, box-shadow .15s ease;
}

.subject-card:hover,
.subject-card:focus-visible {
  transform: translateY(-3px);
}

.subject-card:active {
  transform: translateY(2px);
}

.math-card {
  background: var(--math);
  box-shadow: 0 8px 0 var(--math-shadow);
}

.chinese-card {
  background: var(--chinese);
  box-shadow: 0 8px 0 var(--chinese-shadow);
}

.english-card {
  background: var(--english);
  box-shadow: 0 8px 0 var(--english-shadow);
}

.subject-icon {
  font-size: 3rem;
}

.subject-copy {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.subject-copy strong {
  font-size: 1.55rem;
}

.subject-copy small {
  color: var(--muted);
  font-size: .88rem;
  font-weight: 800;
  letter-spacing: .06em;
  text-transform: uppercase;
}

.subject-copy > span {
  margin-top: 5px;
  color: #445f84;
  font-weight: 600;
}

.status {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 12px;
  border-radius: 999px;
  white-space: nowrap;
  font-size: .85rem;
  font-weight: 800;
}

.status.ready {
  background: var(--sun);
}

.status.soon {
  background: rgba(255, 255, 255, .7);
  color: var(--muted);
}

footer {
  padding: 30px 0 8px;
  color: var(--muted);
  text-align: center;
  font-weight: 600;
}

.placeholder-page {
  padding-top: 24px;
}

.back-link {
  display: inline-flex;
  margin-bottom: 26px;
  padding: 10px 15px;
  border-radius: 14px;
  color: var(--ink);
  background: rgba(255, 255, 255, .7);
  text-decoration: none;
  font-weight: 700;
}

.placeholder-card {
  padding: 48px 24px;
  border: 3px solid rgba(255, 255, 255, .8);
  border-radius: 28px;
  text-align: center;
}

.placeholder-card h1 {
  margin-bottom: 12px;
}

.placeholder-card p:not(.eyebrow) {
  max-width: 480px;
  margin: 0 auto 24px;
  color: #445f84;
  font-size: 1.05rem;
  font-weight: 600;
  line-height: 1.65;
}

.placeholder-icon {
  margin-bottom: 12px;
  font-size: 4rem;
}

@media (max-width: 620px) {
  .subject-card {
    grid-template-columns: auto 1fr;
  }

  .subject-card .status {
    grid-column: 2;
    justify-self: start;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    scroll-behavior: auto !important;
    transition: none !important;
  }
}