:root {
  --bg: #f6f8fc;
  --surface: #ffffff;
  --surface-soft: #edf2fb;
  --line: #d9e2f1;
  --text: #1d2b45;
  --muted: #5f6f8b;
  --brand: #1f5fae;
  --brand-dark: #143d70;
  --accent: #2c7a67;
  --danger: #b91c1c;
  --success: #0f766e;
  --radius: 24px;
  --shadow: 0 18px 42px rgba(17, 31, 61, 0.08);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Manrope", sans-serif;
  background: linear-gradient(180deg, #fbfcff, var(--bg));
  color: var(--text);
  line-height: 1.6;
}

img {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
}

button,
input {
  font: inherit;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: -3rem;
  background: var(--brand-dark);
  color: #fff;
  padding: 0.7rem 1rem;
  border-radius: 999px;
  z-index: 1000;
}

.skip-link:focus {
  top: 1rem;
}

.container {
  width: min(1180px, calc(100% - 2rem));
  margin: 0 auto;
}

.section,
.auth-wrap {
  padding: 3.5rem 0;
}

.section-muted {
  background: rgba(255, 255, 255, 0.58);
}

.section-kicker {
  display: inline-flex;
  width: fit-content;
  margin: 0 0 0.9rem;
  padding: 0.35rem 0.75rem;
  border-radius: 999px;
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  background: rgba(31, 95, 174, 0.08);
  color: var(--brand);
}

.section-heading {
  margin-bottom: 1.35rem;
}

.section-heading h2,
.hero-copy h1 {
  margin: 0;
  line-height: 1.05;
}

.section-heading h2 {
  font-size: clamp(1.85rem, 3.6vw, 2.7rem);
}

.section-heading-inline {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 1.5rem;
}

.section-aside {
  max-width: 36rem;
  color: var(--muted);
  font-size: 0.98rem;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(18px);
  background: rgba(251, 252, 255, 0.9);
  border-bottom: 1px solid rgba(217, 226, 241, 0.72);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  min-height: 78px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.9rem;
  text-decoration: none;
}

.brand-logo {
  width: 56px;
  height: 56px;
  object-fit: contain;
}

.brand-copy {
  display: grid;
}

.brand-copy strong {
  font-size: 1rem;
}

.brand-copy span {
  color: var(--muted);
  font-size: 0.92rem;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 1.15rem;
}

.header-nav a {
  text-decoration: none;
  color: var(--muted);
  font-weight: 700;
  font-size: 0.95rem;
}

.hero-grid,
.auth-grid,
.footer-grid {
  display: grid;
  gap: 1.25rem;
}

.hero-grid {
  grid-template-columns: minmax(0, 1.2fr) minmax(320px, 0.8fr);
  align-items: stretch;
}

.hero-copy,
.hero-panel-card,
.auth-card,
.info-card,
.player-card,
.video-card,
.quick-card,
.sheet-item,
.download-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.hero-copy,
.hero-panel-card,
.auth-card,
.info-card,
.player-card,
.download-card {
  padding: 1.2rem;
}

.hero-copy h1 {
  font-size: clamp(2.25rem, 4.8vw, 3.7rem);
}

.hero-subtitle {
  margin: 0.85rem 0 0;
  font-size: 1.08rem;
  font-weight: 700;
  color: var(--brand-dark);
}

.hero-text {
  margin: 0.85rem 0 0;
  max-width: 52ch;
  color: var(--muted);
  font-size: 0.98rem;
}

.hero-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 1.1rem;
}

.hero-highlights,
.content-list,
.footer-list {
  margin: 0;
  padding-left: 1.1rem;
}

.hero-highlights li,
.content-list li {
  color: var(--muted);
  margin-bottom: 0.45rem;
}

.hero-panel-card {
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.auth-grid {
  grid-template-columns: minmax(0, 0.95fr) minmax(0, 1.05fr);
  align-items: start;
}

.auth-card h2,
.info-card h3 {
  margin: 0;
  font-size: 1.15rem;
}

.auth-card p,
.info-card p {
  color: var(--muted);
  font-size: 0.95rem;
}

.auth-form {
  display: grid;
  gap: 0.7rem;
  margin-top: 0.8rem;
}

.auth-form label {
  display: block;
  margin-bottom: 0.35rem;
  font-size: 0.92rem;
  font-weight: 700;
}

.auth-form input {
  width: 100%;
  border: 1px solid #cbd7e7;
  border-radius: 14px;
  padding: 0.75rem 0.9rem;
  background: #fbfdff;
}

.auth-help {
  font-size: 0.88rem;
}

.auth-message {
  min-height: 1.3rem;
  margin: 0.6rem 0 0;
  font-size: 0.92rem;
  font-weight: 700;
}

.auth-message.error {
  color: var(--danger);
}

.auth-message.success {
  color: var(--success);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  border-radius: 999px;
  padding: 0.8rem 1.15rem;
  font-weight: 800;
  text-decoration: none;
  border: 1px solid transparent;
  cursor: pointer;
}

.btn-primary {
  background: var(--brand);
  color: #fff;
}

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

.protected[hidden] {
  display: none;
}

.protected-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}

.protected-head h2 {
  margin: 0;
  font-size: 1.4rem;
}

.quick-grid,
.videos-grid,
.downloads-grid {
  display: grid;
  gap: 1rem;
}

.quick-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin-bottom: 1rem;
}

.quick-card {
  display: block;
  padding: 0.95rem;
  text-decoration: none;
}

.quick-card-tag {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  margin-bottom: 0.65rem;
  border-radius: 999px;
  background: #edf4ff;
  color: var(--brand);
  font-size: 0.82rem;
  font-weight: 800;
}

.quick-card h3 {
  margin: 0 0 0.25rem;
  font-size: 0.98rem;
}

.quick-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.88rem;
}

.content-section {
  margin-bottom: 1rem;
}

.player-frame {
  width: 100%;
  aspect-ratio: 16 / 9;
  border: none;
  border-radius: 18px;
  background: #0f172a;
}

.player-meta h3 {
  margin: 0.75rem 0 0.25rem;
  font-size: 1.02rem;
}

.player-meta p {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.videos-grid,
.downloads-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.video-card {
  overflow: hidden;
}

.video-thumb {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  background: #e2e8f0;
}

.video-body {
  padding: 0.9rem;
}

.video-body h4,
.download-card h4 {
  margin: 0;
  font-size: 0.96rem;
  line-height: 1.35;
}

.video-body p,
.download-card p {
  margin: 0.35rem 0 0.65rem;
  color: var(--muted);
  font-size: 0.87rem;
}

.video-actions {
  display: flex;
  gap: 0.45rem;
  flex-wrap: wrap;
}

.video-btn,
.yt-btn,
.sheet-download {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  padding: 0.5rem 0.75rem;
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 800;
  text-decoration: none;
  border: 1px solid transparent;
  cursor: pointer;
}

.video-btn {
  background: #edf4ff;
  color: #1d4f88;
  border-color: #c8dbf8;
}

.sheet-btn {
  background: #f2f8f6;
  color: var(--success);
  border-color: #bfe6dd;
}

.yt-btn,
.sheet-download {
  background: #fff;
  color: #334155;
  border-color: #d5dfec;
}

.video-btn[disabled],
.yt-btn.disabled {
  opacity: 0.6;
  cursor: not-allowed;
  pointer-events: none;
}

.sheet-accordion {
  display: grid;
  gap: 0.75rem;
}

.sheet-summary-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-bottom: 0.9rem;
}

.sheet-summary-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.45rem 0.75rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 700;
}

.sheet-item {
  overflow: hidden;
}

.sheet-item summary {
  list-style: none;
  cursor: pointer;
  padding: 0.9rem 1rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.sheet-summary-copy {
  display: grid;
  gap: 0.15rem;
}

.sheet-summary-title {
  color: var(--text);
  line-height: 1.3;
}

.sheet-summary-meta {
  color: var(--muted);
  font-size: 0.8rem;
  font-weight: 700;
}

.sheet-item summary::-webkit-details-marker {
  display: none;
}

.sheet-item summary::after {
  content: "+";
  color: var(--muted);
  font-size: 1.2rem;
}

.sheet-item[open] summary::after {
  content: "−";
}

.sheet-item-body {
  border-top: 1px solid #e2e8f0;
  padding: 0 1rem 1rem;
}

.sheet-item-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin: 0.85rem 0;
}

.sheet-meta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.sheet-body h4 {
  margin: 0.8rem 0 0.2rem;
  font-size: 0.95rem;
}

.sheet-body p,
.sheet-body li {
  color: #475569;
  font-size: 0.88rem;
}

.sheet-body ul,
.sheet-body ol {
  margin: 0.35rem 0 0.7rem;
  padding-left: 1.2rem;
}

.site-footer {
  margin-top: 2.5rem;
  padding: 3.5rem 0 2rem;
  background: #111a30;
  color: #f8fbff;
}

.footer-grid {
  grid-template-columns: 1.2fr 1fr 1fr 1fr;
  align-items: start;
}

.footer-brand-link {
  display: inline-flex;
  align-items: center;
  gap: 0.85rem;
  text-decoration: none;
  margin-bottom: 1rem;
}

.footer-brand-logo {
  width: 56px;
  height: 56px;
  object-fit: contain;
}

.footer-brand-copy {
  display: grid;
}

.footer-brand-copy strong {
  color: #fff;
}

.footer-brand-copy span {
  color: #89a7dd;
}

.footer-brand p,
.footer-list li,
.footer-list a {
  color: rgba(248, 251, 255, 0.78);
}

.footer-grid h3 {
  margin: 0 0 0.95rem;
  font-size: 1rem;
  color: #fff;
}

.footer-list {
  list-style: none;
  padding: 0;
}

.footer-list li {
  margin-bottom: 0.7rem;
}

.footer-list a {
  text-decoration: none;
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  color: rgba(248, 251, 255, 0.58);
}

@media (max-width: 980px) {
  .hero-grid,
  .auth-grid,
  .footer-grid,
  .videos-grid,
  .downloads-grid,
  .section-heading-inline {
    grid-template-columns: 1fr;
  }

  .quick-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .section-heading-inline {
    align-items: start;
  }

  .header-inner {
    flex-direction: column;
    align-items: start;
    padding: 0.85rem 0;
  }

  .header-nav {
    flex-wrap: wrap;
    gap: 0.85rem;
  }
}

@media (max-width: 640px) {
  .container {
    width: min(100% - 1.25rem, 100%);
  }

  .section,
  .auth-wrap {
    padding: 2.5rem 0;
  }

  .hero-copy,
  .hero-panel-card,
  .auth-card,
  .info-card,
  .player-card,
  .download-card {
    padding: 1rem;
  }

  .brand-copy strong,
  .brand-copy span {
    line-height: 1.2;
  }

  .hero-actions {
    flex-direction: column;
  }

  .hero-actions .btn,
  .auth-form .btn {
    width: 100%;
  }

  .quick-grid {
    grid-template-columns: 1fr;
  }
}