:root {
  color-scheme: light;
  --ink: #1d2433;
  --muted: #657084;
  --line: #dfe5ee;
  --soft: #f5f7fb;
  --brand: #0c5c59;
  --brand-2: #1e8b7b;
  --accent: #d29b32;
  --danger: #d94b4b;
  --white: #fff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(circle at 18% 0%, rgba(30, 139, 123, 0.18), transparent 32%),
    linear-gradient(180deg, #eef5f4 0%, #f7f8fb 44%, #ffffff 100%);
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

button,
input {
  font: inherit;
}

.app-shell {
  width: min(100%, 480px);
  min-height: 100vh;
  margin: 0 auto;
  background: rgba(255, 255, 255, 0.72);
  box-shadow: 0 0 40px rgba(24, 35, 52, 0.08);
}

.screen {
  min-height: 100vh;
  padding: max(18px, env(safe-area-inset-top)) 18px max(22px, env(safe-area-inset-bottom));
}

.hero {
  padding: 22px 18px 20px;
  color: #fff;
  background:
    linear-gradient(145deg, rgba(12, 92, 89, 0.96), rgba(12, 58, 74, 0.95)),
    url("data:image/svg+xml,%3Csvg width='420' height='260' viewBox='0 0 420 260' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M-30 210C48 176 73 62 158 73c85 11 92 128 182 102 51-15 72-60 112-68v172H-30Z' fill='%23ffffff' fill-opacity='.08'/%3E%3Cpath d='M307 18h80v80h-80zM265 116h35v35h-35zM40 35h54v54H40z' fill='%23ffffff' fill-opacity='.08'/%3E%3C/svg%3E");
  background-size: cover;
  border-bottom-left-radius: 22px;
  border-bottom-right-radius: 22px;
}

.brand-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.brand-mark {
  display: inline-grid;
  place-items: center;
  min-width: 68px;
  height: 34px;
  padding: 0 10px;
  font-weight: 800;
  letter-spacing: 0.08em;
  color: #0d5a57;
  background: #fff;
  border-radius: 6px;
}

.culture-tag {
  color: rgba(255, 255, 255, 0.78);
  font-size: 12px;
}

.hero h1 {
  margin: 24px 0 10px;
  font-size: 28px;
  line-height: 1.16;
  letter-spacing: 0;
}

.hero p {
  margin: 0;
  color: rgba(255, 255, 255, 0.82);
  line-height: 1.7;
}

.panel {
  margin: 16px 0;
  padding: 16px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 10px;
}

.field {
  display: grid;
  gap: 8px;
  margin-bottom: 14px;
}

.field label {
  font-size: 14px;
  font-weight: 700;
}

.field input {
  width: 100%;
  height: 46px;
  padding: 0 12px;
  color: var(--ink);
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  outline: none;
}

.field input:focus {
  border-color: var(--brand-2);
  box-shadow: 0 0 0 3px rgba(30, 139, 123, 0.12);
}

.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  margin-top: 16px;
}

.step {
  padding: 10px 8px;
  color: var(--muted);
  font-size: 12px;
  text-align: center;
  background: rgba(255, 255, 255, 0.76);
  border: 1px solid rgba(255, 255, 255, 0.35);
  border-radius: 8px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 48px;
  padding: 0 16px;
  color: #fff;
  font-weight: 700;
  background: var(--brand);
  border: 0;
  border-radius: 8px;
}

.btn.secondary {
  color: var(--brand);
  background: #e7f3f0;
}

.btn.ghost {
  color: var(--ink);
  background: #fff;
  border: 1px solid var(--line);
}

.btn:disabled {
  opacity: 0.48;
}

.screen-loading,
.screen-state {
  display: grid;
  place-items: center;
  text-align: center;
}

.state-card {
  width: 100%;
  padding: 28px 18px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
}

.progress-head {
  position: sticky;
  top: 0;
  z-index: 2;
  padding: max(14px, env(safe-area-inset-top)) 18px 12px;
  background: rgba(247, 248, 251, 0.94);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}

.progress-text {
  display: flex;
  justify-content: space-between;
  margin-bottom: 10px;
  color: var(--muted);
  font-size: 13px;
}

.bar {
  height: 8px;
  overflow: hidden;
  background: #e4e9f1;
  border-radius: 999px;
}

.bar span {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, var(--brand), var(--accent));
  border-radius: inherit;
}

.question-title {
  margin: 18px 0 8px;
  font-size: 22px;
}

.question-tip {
  margin: 0 0 14px;
  color: var(--muted);
  line-height: 1.6;
}

.video-list {
  display: grid;
  gap: 12px;
}

.video-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 10px;
  overflow: hidden;
}

.video-frame {
  width: 100%;
  aspect-ratio: 9 / 16;
  max-height: 68vh;
  background: #101820;
}

.video-frame video {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.video-body {
  padding: 12px;
}

.video-title-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 34px;
  height: 28px;
  color: var(--brand);
  font-weight: 800;
  background: #e7f3f0;
  border-radius: 6px;
}

.rank-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  margin-top: 12px;
}

.rank-btn {
  min-height: 40px;
  color: var(--ink);
  background: var(--soft);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.rank-btn.active {
  color: #fff;
  background: var(--brand);
  border-color: var(--brand);
}

.footer-actions {
  position: sticky;
  bottom: 0;
  display: grid;
  grid-template-columns: 1fr 1.35fr;
  gap: 10px;
  padding: 12px 18px max(14px, env(safe-area-inset-bottom));
  background: rgba(255, 255, 255, 0.94);
  border-top: 1px solid var(--line);
  backdrop-filter: blur(12px);
}

.toast {
  position: fixed;
  right: 18px;
  bottom: 86px;
  left: 18px;
  z-index: 10;
  max-width: 444px;
  margin: 0 auto;
  padding: 12px 14px;
  color: #fff;
  text-align: center;
  background: rgba(28, 35, 45, 0.92);
  border-radius: 8px;
}

.success-icon {
  display: grid;
  place-items: center;
  width: 58px;
  height: 58px;
  margin: 0 auto 16px;
  color: #fff;
  font-size: 28px;
  background: var(--brand-2);
  border-radius: 50%;
}