/* ═══════════════════════════════════════════════════════════
   QEDream – main.css
   Design System · Components · Layout
═══════════════════════════════════════════════════════════ */

/* ─── 1. CSS CUSTOM PROPERTIES ───────────────────────────── */
:root {
  /* Palette */
  --color-bg:          #080a0f;
  --color-surface:     #0d1117;
  --color-surface-2:   #111827;
  --color-glass:       rgba(255, 255, 255, 0.04);
  --color-glass-border:rgba(255, 255, 255, 0.09);
  --color-glass-hover: rgba(255, 255, 255, 0.07);

  --color-white:       #ffffff;
  --color-off-white:   #e8eaf0;
  --color-muted:       rgba(255,255,255,0.45);
  --color-muted-2:     rgba(255,255,255,0.28);

  --color-accent:      #7c9eff;         /* cool-blue glow */
  --color-accent-2:    #a78bfa;         /* violet */
  --color-accent-3:    #34d399;         /* emerald (check mark) */
  --color-glow:        rgba(124,158,255,0.18);
  --color-glow-strong: rgba(124,158,255,0.35);

  --color-dark-text:    #0d1117;
  --color-dark-muted:   rgba(13,17,23,0.6);

  /* Typography */
  --font-sans:   'Inter', system-ui, -apple-system, sans-serif;
  --font-serif:  'Playfair Display', Georgia, serif;
  --font-mono:   'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing scale */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Borders & radii */
  --radius-sm:  0.375rem;
  --radius-md:  0.75rem;
  --radius-lg:  1.25rem;
  --radius-xl:  2rem;
  --radius-pill:9999px;

  /* Shadows */
  --shadow-glow:   0 0 40px rgba(124,158,255,0.15);
  --shadow-card:   0 4px 32px rgba(0,0,0,0.5);
  --shadow-strong: 0 8px 64px rgba(0,0,0,0.7);

  /* Transitions */
  --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in-out:   cubic-bezier(0.4, 0, 0.2, 1);
  --duration-fast: 200ms;
  --duration-med:  400ms;
  --duration-slow: 700ms;

  /* Nav */
  --nav-height: 72px;
}

/* ─── 2. RESET & BASE ─────────────────────────────────────── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg);
  color: var(--color-white);
  overflow-x: hidden;
  line-height: 1.6;
}

img { max-width: 100%; height: auto; display: block; }
a { text-decoration: none; color: inherit; }
ul { list-style: none; padding: 0; margin: 0; }
button { cursor: pointer; border: none; background: none; }

/* ─── 3. NAVIGATION ──────────────────────────────────────── */
.qed-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  transition: background var(--duration-med) var(--ease-in-out),
              backdrop-filter var(--duration-med) var(--ease-in-out),
              border-color var(--duration-med) var(--ease-in-out),
              transform var(--duration-med) var(--ease-in-out),
              box-shadow var(--duration-med) var(--ease-in-out);
  border-bottom: 1px solid transparent;
}

.qed-nav.nav-scrolled {
  background: rgba(8, 10, 15, 0.72);
  backdrop-filter: blur(20px) saturate(1.4);
  -webkit-backdrop-filter: blur(20px) saturate(1.4);
  border-bottom-color: var(--color-glass-border);
  box-shadow: 0 1px 0 rgba(255,255,255,0.04);
}

.qed-nav.nav-hidden {
  transform: translateY(-100%);
}

.nav-inner {
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--space-8);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Brand */
.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
}
.nav-logo {
  width: 36px;
  height: 36px;
  object-fit: contain;
  filter: drop-shadow(0 0 8px var(--color-accent));
}
.nav-wordmark {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.01em;
  color: var(--color-white);
  background: linear-gradient(135deg, #fff 0%, var(--color-accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Nav links */
.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.nav-link-item {
  position: relative;
  padding: var(--space-2) var(--space-4);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-muted);
  letter-spacing: 0.02em;
  transition: color var(--duration-fast) var(--ease-in-out);
  text-decoration: none;
  display: inline-block;
}
.nav-link-item::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  right: 50%;
  height: 1px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-accent-2));
  transition: left var(--duration-med) var(--ease-out-expo),
              right var(--duration-med) var(--ease-out-expo);
  border-radius: var(--radius-pill);
}
.nav-link-item:hover {
  color: var(--color-white);
  text-shadow: 0 0 20px var(--color-glow-strong);
}
.nav-link-item:hover::after {
  left: var(--space-4);
  right: var(--space-4);
}

/* Hamburger (mobile) */
.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: var(--space-2);
  z-index: 100;
}
.nav-hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-white);
  border-radius: var(--radius-pill);
  transition: transform var(--duration-med) var(--ease-out-expo),
              opacity var(--duration-fast) var(--ease-in-out);
  transform-origin: center;
}
.nav-hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-hamburger.open span:nth-child(2) { opacity: 0; }
.nav-hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ─── 4. HERO SECTION ────────────────────────────────────── */
.hero-section {
  position: relative;
  width: 100%;
  height: 100dvh;
  min-height: 600px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

/* Background carousel */
.hero-carousel {
  position: absolute;
  inset: 0;
  z-index: 0;
}
.hero-slide {
  position: absolute;
  inset: -5%;       /* extra space for Ken Burns zoom */
  background-size: cover;
  background-position: center;
  opacity: 0;
  transition: opacity 1.4s ease-in-out;
  will-change: opacity, transform;
}
.hero-slide.active {
  opacity: 1;
}
.hero-slide.zoom-active {
  animation: kenBurns 8s ease-in-out forwards;
}

/* Fallback gradient when images not loaded */
.hero-carousel::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, #0a0e1a 0%, #0d1520 50%, #0b1219 100%);
  z-index: -1;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg,
      rgba(8,10,15,0.3) 0%,
      rgba(8,10,15,0.5) 40%,
      rgba(8,10,15,0.85) 100%),
    radial-gradient(ellipse at 50% 80%, rgba(124,158,255,0.08) 0%, transparent 70%);
  backdrop-filter: blur(2px);
  -webkit-backdrop-filter: blur(2px);
}

/* Hero content */
.hero-content {
  position: relative;
  z-index: 2;
  padding-top: var(--nav-height);
}

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-6);
  opacity: 0;
  transform: translateY(20px);
}
.eyebrow-dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--color-accent);
  box-shadow: 0 0 8px var(--color-accent);
  flex-shrink: 0;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(4rem, 12vw, 9rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-5);
  opacity: 0;
  transform: translateY(30px);
}
.hero-title-main {
  background: linear-gradient(
    135deg,
    #ffffff 0%,
    #c8d8ff 35%,
    var(--color-accent) 65%,
    var(--color-accent-2) 100%
  );
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: inline-block;
  filter: drop-shadow(0 0 60px rgba(124,158,255,0.25));
}

.hero-slogan {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: clamp(1.1rem, 2.5vw, 1.65rem);
  color: var(--color-off-white);
  letter-spacing: 0.01em;
  margin-bottom: var(--space-4);
  opacity: 0;
  transform: translateY(24px);
}

.hero-subtitle {
  font-size: clamp(0.9rem, 1.5vw, 1.05rem);
  font-weight: 400;
  color: var(--color-muted);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: var(--space-8);
  opacity: 0;
  transform: translateY(22px);
}

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  justify-content: center;
  margin-bottom: var(--space-10);
  opacity: 0;
  transform: translateY(20px);
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-5);
  background: var(--color-glass);
  border: 1px solid var(--color-glass-border);
  border-radius: var(--radius-pill);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-off-white);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  letter-spacing: 0.01em;
}
.hero-badge svg { flex-shrink: 0; color: var(--color-accent-3); }

.hero-cta {
  display: flex;
  gap: var(--space-4);
  justify-content: center;
  flex-wrap: wrap;
  transform: translateY(20px);
}

.hero-cta-2 {
  display: flex;
  gap: var(--space-4);
  flex-wrap: wrap;
  transform: translateY(20px);
}

/* Buttons */
.btn-qed-primary {
  display: inline-flex;
  align-items: center;
  padding: var(--space-4) var(--space-8);
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-2));
  color: #fff;
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  border-radius: var(--radius-pill);
  box-shadow: 0 4px 24px rgba(124,158,255,0.35), inset 0 1px 0 rgba(255,255,255,0.2);
  transition: transform var(--duration-fast) var(--ease-out-expo),
              box-shadow var(--duration-fast) var(--ease-out-expo),
              filter var(--duration-fast) var(--ease-in-out);
}
.btn-qed-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 40px rgba(124,158,255,0.5), inset 0 1px 0 rgba(255,255,255,0.25);
  filter: brightness(1.08);
  color: #fff;
}
.btn-qed-primary:active { transform: translateY(0); }

.btn-qed-ghost {
  display: inline-flex;
  align-items: center;
  padding: var(--space-4) var(--space-8);
  background: transparent;
  color: var(--color-off-white);
  font-size: 0.95rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  border-radius: var(--radius-pill);
  border: 1px solid var(--color-glass-border);
  transition: background var(--duration-fast) var(--ease-in-out),
              border-color var(--duration-fast) var(--ease-in-out),
              transform var(--duration-fast) var(--ease-out-expo);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}
.btn-qed-ghost:hover {
  background: var(--color-glass-hover);
  border-color: rgba(255,255,255,0.2);
  transform: translateY(-2px);
  color: var(--color-white);
}

.btn-qed-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 40px rgba(124, 158, 255, 0.5), inset 0 1px 0 rgba(255, 255, 255, 0.25);
    filter: brightness(1.08);
    color: #fff;
}

.btn-qed-primary:active {
    transform: translateY(0);
}

.btn-qed-secondary {
    position: relative;
    display: inline-flex;
    align-items: center;
    padding: var(--space-4) var(--space-8);
    background: none;
    color: var(--color-accent);
    font-size: 1rem;
    font-weight: 500;
    letter-spacing: 0.02em;
    border-radius: var(--radius-pill);
    border: 3px solid var(--color-accent);
    overflow: hidden;

    /* important */
    z-index: 0;
}

.btn-qed-secondary::before {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, var(--color-accent), var(--color-accent-2));
    opacity: 0.1;
    border-radius: inherit;
    pointer-events: none;

    /* push it behind */
    z-index: -1;
}

.btn-qed-secondary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 40px rgba(124, 158, 255, 0.5), inset 0 1px 0 rgba(255, 255, 255, 0.25);
    filter: brightness(1.08);
    color: var(--color-accent);
}


/* Scroll indicator */
.scroll-indicator {
  position: absolute;
  bottom: var(--space-8);
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: center;
}
.scroll-line {
  width: 1px;
  height: 60px;
  background: linear-gradient(to bottom, rgba(255,255,255,0), rgba(255,255,255,0.4));
  animation: scrollPulse 2s ease-in-out infinite;
}

/* ─── 5. SECTION COMMON ───────────────────────────────────── */
.section-header {
  margin-bottom: var(--space-16);
}
.section-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-4);
  padding: var(--space-1) var(--space-4);
  background: rgba(124,158,255,0.1);
  border: 1px solid rgba(124,158,255,0.2);
  border-radius: var(--radius-pill);
}
.section-tag--dark {
  color: #5b6cf6;
  background: rgba(91,108,246,0.08);
  border-color: rgba(91,108,246,0.18);
}

.section-title {
  font-family: var(--font-serif);
  font-size: clamp(2.2rem, 5vw, 3.8rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.1;
  color: var(--color-white);
  margin-bottom: var(--space-5);
}
.section-title--dark { color: var(--color-dark-text); }

.section-lead {
  font-size: 1.1rem;
  line-height: 1.7;
  color: var(--color-muted);
  max-width: 640px;
}
.section-lead--dark { color: rgba(13,17,23,0.7); }

/* ─── 6. STUDENTS SECTION ────────────────────────────────── */
.students-section {
  position: relative;
  background: var(--color-surface);
  padding: var(--space-32) 0;
  overflow: hidden;
  /* Slide over hero with z-index */
  z-index: 2;
}

.section-bg-noise {
  position: absolute;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)' opacity='0.04'/%3E%3C/svg%3E");
  background-size: 200px;
  pointer-events: none;
  opacity: 0.5;
}

/* Feature cards grid */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-5);
  margin-bottom: var(--space-16);
}
.feature-card {
  background: var(--color-glass);
  border: 1px solid var(--color-glass-border);
  border-radius: var(--radius-lg);
  padding: var(--space-8) var(--space-6);
  transition: background var(--duration-med) var(--ease-in-out),
              border-color var(--duration-med) var(--ease-in-out),
              transform var(--duration-med) var(--ease-out-expo),
              box-shadow var(--duration-med) var(--ease-in-out);
  position: relative;
  overflow: hidden;
}
.feature-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(124,158,255,0.4), transparent);
  opacity: 0;
  transition: opacity var(--duration-med) var(--ease-in-out);
}
.feature-card:hover {
  background: var(--color-glass-hover);
  border-color: rgba(124,158,255,0.25);
  transform: translateY(-4px);
  box-shadow: var(--shadow-glow);
}
.feature-card:hover::before { opacity: 1; }

.feature-icon {
  width: 48px;
  height: 48px;
  margin-bottom: var(--space-5);
  color: var(--color-accent);
}
.feature-icon svg { width: 100%; height: 100%; }
.feature-card h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: var(--space-3);
  letter-spacing: -0.01em;
}
.feature-card p {
  font-size: 0.88rem;
  line-height: 1.65;
  color: var(--color-muted);
}

/* ─── 7. REGISTERED TUTORS ──────────────────────────────── */
.tutors-registered {
  margin-bottom: var(--space-16);
}

.tutors-registered-title {
  font-family: var(--font-serif);
  font-size: 1.45rem;
  font-weight: 600;
  color: var(--color-dark-text);
  letter-spacing: -0.01em;
  margin-bottom: var(--space-8);
}

.tutor-cards-grid {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

.tutor-card {
  display: flex;
  gap: var(--space-6);
  background: #fff;
  border: 1px solid rgba(13,17,23,0.09);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: transform var(--duration-med) var(--ease-out-expo),
              box-shadow var(--duration-med) var(--ease-in-out),
              border-color var(--duration-med) var(--ease-in-out);
}

.tutor-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 40px rgba(91,108,246,0.10);
  border-color: rgba(91,108,246,0.2);
}

.tutor-card-photo {
  flex-shrink: 0;
  width: 96px;
  height: 96px;
  border-radius: var(--radius-md);
  overflow: hidden;
  object-fit: cover;
}

.tutor-card-photo--placeholder {
  background: linear-gradient(135deg,
    rgba(91,108,246,0.08) 0%,
    rgba(167,139,250,0.06) 100%);
  border: 1px dashed rgba(91,108,246,0.2);
}

.tutor-card-body {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.tutor-card-name {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-dark-text);
  letter-spacing: -0.01em;
  margin-bottom: var(--space-1);
}

.tutor-card-bio {
  font-size: 0.88rem;
  line-height: 1.75;
  color: rgba(13,17,23,0.6);
  margin: 0;
}

@media (max-width: 480px) {
  .tutor-card {
    flex-direction: column;
  }
  .tutor-card-photo {
    width: 72px;
    height: 72px;
  }
}

/* ─── 8. COUNTDOWN ───────────────────────────────────────── */
.countdown-block {
  text-align: center;
  padding: var(--space-12) var(--space-8);
  background: linear-gradient(135deg,
    rgba(124,158,255,0.06) 0%,
    rgba(167,139,250,0.06) 100%);
  border: 1px solid rgba(124,158,255,0.15);
  border-radius: var(--radius-xl);
  position: relative;
  overflow: hidden;
}
.countdown-block::before {
  content: '';
  position: absolute;
  top: -50%; left: -50%;
  width: 200%; height: 200%;
  background: radial-gradient(ellipse at center, rgba(124,158,255,0.05) 0%, transparent 60%);
  pointer-events: none;
}
.countdown-block--light {
  background: linear-gradient(135deg,
    rgba(91,108,246,0.06) 0%,
    rgba(91,108,246,0.02) 100%);
  border-color: rgba(91,108,246,0.15);
}

.countdown-label {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-muted);
  margin-bottom: var(--space-8);
}
.countdown-label--dark { color: rgba(13,17,23,0.5); }

.countdown-timer {
  display: flex;
  align-items: flex-end;
  justify-content: center;
  gap: var(--space-6);
  margin-bottom: var(--space-6);
}
.countdown-unit {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
}
.countdown-number {
  font-family: var(--font-mono);
  font-size: clamp(2.8rem, 6vw, 5rem);
  font-weight: 500;
  line-height: 1;
  color: var(--color-white);
  background: linear-gradient(135deg, #fff 0%, var(--color-accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  min-width: 2.2ch;
  text-align: center;
  transition: transform 0.3s var(--ease-out-expo);
  display: inline-block;
}
.countdown-number--dark {
  background: linear-gradient(135deg, #0d1117 0%, #5b6cf6 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.countdown-number.tick {
  animation: tickFlip 0.3s var(--ease-out-expo);
}
.countdown-unit-label {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-muted-2);
}
.countdown-unit-label--dark { color: rgba(13,17,23,0.4); }
.countdown-sep {
  font-family: var(--font-mono);
  font-size: clamp(2.2rem, 4vw, 3.8rem);
  font-weight: 300;
  color: var(--color-muted-2);
  padding-bottom: 0.4rem;
  line-height: 1;
  align-self: center;
}
.countdown-sep--dark { color: rgba(13,17,23,0.25); }
.countdown-date-display {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: 1.05rem;
  color: var(--color-muted);
}
.countdown-date-display--dark { color: rgba(13,17,23,0.5); }

/* ─── 9. TEACHERS SECTION ────────────────────────────────── */
.teachers-section {
  background: #f4f5f9;
  padding: var(--space-32) 0;
  position: relative;
  z-index: 3;
}

/* Topics grid */
.topics-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-4);
  margin-bottom: var(--space-16);
}
.topic-card {
  background: #fff;
  border: 1px solid rgba(13,17,23,0.08);
  border-radius: var(--radius-lg);
  padding: var(--space-8) var(--space-6);
  position: relative;
  transition: transform var(--duration-med) var(--ease-out-expo),
              box-shadow var(--duration-med) var(--ease-in-out),
              border-color var(--duration-med) var(--ease-in-out);
  overflow: hidden;
}
.topic-card::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-accent-2));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--duration-med) var(--ease-out-expo);
}
.topic-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 12px 40px rgba(91,108,246,0.12);
  border-color: rgba(91,108,246,0.2);
}
.topic-card:hover::after { transform: scaleX(1); }
.topic-glyph {
  display: block;
  font-size: 2.6rem;
  color: var(--color-accent);
  margin-bottom: var(--space-4);
  line-height: 1;
  font-weight: 300;
}
.topic-card h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-dark-text);
  margin-bottom: var(--space-3);
  letter-spacing: -0.01em;
}
.topic-card p {
  font-size: 0.85rem;
  line-height: 1.6;
  color: rgba(13,17,23,0.55);
}

/* Expectations block */
.expectations-block {
  margin-bottom: var(--space-16);
}
.expectations-title {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-dark-text);
  margin-bottom: var(--space-8);
  letter-spacing: -0.01em;
}
.expectations-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}
.expectation-item {
  display: grid;
  grid-template-columns: 3rem 1fr;
  gap: var(--space-6);
  padding: var(--space-6) 0;
  border-bottom: 1px solid rgba(13,17,23,0.07);
  align-items: start;
  transition: background var(--duration-fast) var(--ease-in-out);
}
.expectation-item:last-child { border-bottom: none; }
.expectation-num {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 500;
  color: #5b6cf6;
  letter-spacing: 0.05em;
  padding-top: var(--space-1);
}
.expectation-item strong {
  display: block;
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-dark-text);
  margin-bottom: var(--space-2);
  letter-spacing: -0.01em;
}
.expectation-item p {
  font-size: 0.9rem;
  line-height: 1.65;
  color: rgba(13,17,23,0.6);
  margin: 0;
}

/* ─── 8b. SUBJECT TYPE CARDS ─────────────────────────────── */
.subject-types-block {
  margin-bottom: var(--space-16);
}

.subject-types-title {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-dark-text);
  margin-bottom: var(--space-3);
  letter-spacing: -0.01em;
}

.subject-types-lead {
  font-size: 0.95rem;
  line-height: 1.7;
  color: rgba(13,17,23,0.55);
  margin-bottom: var(--space-8);
  max-width: 620px;
}

.subject-types-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-5);
}

/* Base card */
.subject-card {
  background: #fff;
  border: 1px solid rgba(13,17,23,0.09);
  border-radius: var(--radius-lg);
  padding: var(--space-8) var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  position: relative;
  overflow: hidden;
  transition: transform var(--duration-med) var(--ease-out-expo),
              box-shadow var(--duration-med) var(--ease-in-out);
}

/* Coloured top-border accent */
.subject-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  border-radius: var(--radius-lg) var(--radius-lg) 0 0;
  transition: opacity var(--duration-med) var(--ease-in-out);
  opacity: 0.7;
}
.subject-card--easy::before  { background: linear-gradient(90deg, #34d399, #6ee7b7); }
.subject-card--hard::before  { background: linear-gradient(90deg, #f87171, #fb923c); }
.subject-card--session::before { background: linear-gradient(90deg, #7c9eff, #a78bfa); }

.subject-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 14px 44px rgba(13,17,23,0.10);
}
.subject-card:hover::before { opacity: 1; }

/* Header row */
.subject-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
}

.subject-card-badge {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-pill);
  background: rgba(91,108,246,0.08);
  border: 1px solid rgba(91,108,246,0.18);
  color: #5b6cf6;
  white-space: nowrap;
}
.subject-card-badge--session {
  background: rgba(124,158,255,0.08);
  border-color: rgba(124,158,255,0.2);
  color: #7c9eff;
}

.subject-card-level {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-pill);
  white-space: nowrap;
}
.subject-card-level--easy {
  background: rgba(52,211,153,0.12);
  border: 1px solid rgba(52,211,153,0.28);
  color: #059669;
}
.subject-card-level--hard {
  background: rgba(248,113,113,0.12);
  border: 1px solid rgba(248,113,113,0.28);
  color: #dc2626;
}
.subject-card-level--session {
  background: rgba(167,139,250,0.12);
  border: 1px solid rgba(167,139,250,0.28);
  color: #7c3aed;
}

/* Title */
.subject-card-title {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-dark-text);
  letter-spacing: -0.01em;
  margin: 0;
}

/* Description */
.subject-card-desc {
  font-size: 0.875rem;
  line-height: 1.65;
  color: rgba(13,17,23,0.58);
  margin: 0;
  flex: 1;
}

/* Meta list */
.subject-card-meta {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  border-top: 1px solid rgba(13,17,23,0.07);
  padding-top: var(--space-4);
}
.subject-card-meta li {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 0.83rem;
  color: rgba(13,17,23,0.62);
}
.subject-card-meta li svg {
  width: 14px;
  height: 14px;
  flex-shrink: 0;
  color: #5b6cf6;
  opacity: 0.8;
}
.subject-card--easy   .subject-card-meta li svg { color: #059669; }
.subject-card--hard   .subject-card-meta li svg { color: #dc2626; }
.subject-card--session .subject-card-meta li svg { color: #7c3aed; }

/* Difficulty block */
.subject-card-difficulty {
  border-top: 1px solid rgba(13,17,23,0.07);
  padding-top: var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.diff-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: rgba(13,17,23,0.38);
}

.diff-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.diff-item {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 0.78rem;
  font-weight: 500;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-sm);
  white-space: nowrap;
}
.diff-item svg {
  width: 12px;
  height: 12px;
  flex-shrink: 0;
}

.diff-item--avg {
  background: rgba(52,211,153,0.10);
  color: #065f46;
  border: 1px solid rgba(52,211,153,0.22);
}
.diff-item--max {
  background: rgba(248,113,113,0.10);
  color: #991b1b;
  border: 1px solid rgba(248,113,113,0.22);
}

/* Session overrides – no hard difficulty */
.diff-item--relaxed {
  background: rgba(124,158,255,0.10);
  color: #1e3a8a;
  border: 1px solid rgba(124,158,255,0.22);
}
.diff-item--none {
  background: rgba(13,17,23,0.05);
  color: rgba(13,17,23,0.40);
  border: 1px solid rgba(13,17,23,0.10);
  text-decoration: none;
}

/* ─── 10. ABOUT SECTION ───────────────────────────────────── */
.about-section {
  position: relative;
  padding: var(--space-32) 0;
  overflow: hidden;
  z-index: 2;
}
.about-bg {
  position: absolute;
  inset: -10%;
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
  filter: blur(4px) brightness(0.4);
  transform: scale(1.1);
}

/* Fallback gradient */
.about-bg::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, #0a1628 0%, #0d2040 100%);
  z-index: -1;
}

.about-overlay {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(8,10,15,0.75) 0%, rgba(8,10,15,0.6) 50%, rgba(8,10,15,0.85) 100%),
    radial-gradient(ellipse at 30% 60%, rgba(124,158,255,0.08) 0%, transparent 60%);
}
.about-container {
  position: relative;
  z-index: 2;
}

/* About cards */
.about-card {
  background: var(--color-glass);
  border: 1px solid var(--color-glass-border);
  border-radius: var(--radius-xl);
  padding: var(--space-10) var(--space-8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  height: 100%;
  transition: border-color var(--duration-med) var(--ease-in-out),
              box-shadow var(--duration-med) var(--ease-in-out);
}
.about-card:hover {
  border-color: rgba(124,158,255,0.2);
  box-shadow: var(--shadow-glow);
}

.about-logo-wrap {
  width: 64px;
  height: 64px;
  border-radius: var(--radius-md);
  background: rgba(124,158,255,0.1);
  border: 1px solid rgba(124,158,255,0.2);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-6);
  padding: var(--space-3);
}
.about-partner-logo {
  width: 100%;
  height: 100%;
  object-fit: contain;
  filter: brightness(1) drop-shadow(0 0 4px rgba(124,158,255,0.3));
}
.about-icon-wrap {
  width: 64px;
  height: 64px;
  color: var(--color-accent);
  margin-bottom: var(--space-6);
}
.about-icon-wrap svg { width: 100%; height: 100%; }

.about-card-title {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: var(--space-4);
  letter-spacing: -0.01em;
}
.about-card-text {
  font-size: 0.95rem;
  line-height: 1.75;
  color: var(--color-muted);
  margin-bottom: var(--space-6);
}
.about-card-text strong { color: var(--color-off-white); }

.about-pill {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: var(--space-1) var(--space-4);
  background: rgba(52,211,153,0.1);
  border: 1px solid rgba(52,211,153,0.25);
  color: var(--color-accent-3);
  border-radius: var(--radius-pill);
}

.about-feature-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}
.about-feature-list li {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 0.9rem;
  color: var(--color-muted);
}
.about-feature-list li::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-2));
  flex-shrink: 0;
  box-shadow: 0 0 6px var(--color-accent);
}

/* Contact */
.about-contact {
  text-align: center;
  margin-top: var(--space-20);
  padding-top: var(--space-16);
  border-top: 1px solid var(--color-glass-border);
}
.about-contact-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-muted-2);
  margin-bottom: var(--space-4);
}
.about-contact-email {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 1.3rem;
  font-weight: 500;
  color: var(--color-off-white);
  letter-spacing: -0.01em;
  transition: color var(--duration-fast) var(--ease-in-out),
              text-shadow var(--duration-fast) var(--ease-in-out);
}
.about-contact-email:hover {
  color: var(--color-accent);
  text-shadow: 0 0 30px rgba(124,158,255,0.4);
}
.about-contact-email svg { flex-shrink: 0; }

/* ─── 11. NOTIFY FORM ────────────────────────────────────── */
.notify-form-wrap {
  margin-top: var(--space-6);
  text-align: center;
  padding: var(--space-10) var(--space-8);
  background: linear-gradient(135deg,
    rgba(124,158,255,0.05) 0%,
    rgba(167,139,250,0.05) 100%);
  border: 1px solid rgba(124,158,255,0.12);
  border-radius: var(--radius-xl);
}
.notify-form-wrap--light {
  background: linear-gradient(135deg,
    rgba(91,108,246,0.05) 0%,
    rgba(91,108,246,0.02) 100%);
  border-color: rgba(91,108,246,0.12);
}

.notify-label {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--color-muted);
  margin-bottom: var(--space-5);
}
.notify-label--dark {
  color: rgba(13,17,23,0.5);
}

.notify-form {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-3);
}

.notify-input-group {
  display: flex;
  width: 100%;
  max-width: 480px;
  border-radius: var(--radius-pill);
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(124,158,255,0.2);
  overflow: hidden;
  transition: border-color var(--duration-fast) var(--ease-in-out),
              box-shadow var(--duration-fast) var(--ease-in-out);
}
.notify-input-group:focus-within {
  border-color: rgba(124,158,255,0.55);
  box-shadow: 0 0 0 3px rgba(124,158,255,0.1);
}

.notify-form--light .notify-input-group {
  background: rgba(255,255,255,0.9);
  border-color: rgba(91,108,246,0.2);
}
.notify-form--light .notify-input-group:focus-within {
  border-color: rgba(91,108,246,0.5);
  box-shadow: 0 0 0 3px rgba(91,108,246,0.1);
}

.notify-input {
  flex: 1;
  min-width: 0;
  padding: var(--space-3) var(--space-6);
  background: transparent;
  border: none;
  outline: none;
  font-family: var(--font-sans);
  font-size: 0.93rem;
  color: var(--color-white);
}
.notify-input::placeholder { color: var(--color-muted-2); }

.notify-input--light {
  color: var(--color-dark-text);
}
.notify-input--light::placeholder { color: rgba(13,17,23,0.38); }

.notify-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
  padding: var(--space-3) var(--space-6);
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-2));
  color: #fff;
  font-family: var(--font-sans);
  font-size: 0.88rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  border: none;
  border-radius: 0 var(--radius-pill) var(--radius-pill) 0;
  cursor: pointer;
  transition: filter var(--duration-fast) var(--ease-in-out),
              transform var(--duration-fast) var(--ease-out-expo);
  white-space: nowrap;
}
.notify-btn:hover {
  filter: brightness(1.1);
}
.notify-btn:active { transform: scale(0.97); }

.notify-btn--light {
  background: linear-gradient(135deg, #5b6cf6, #7c9eff);
}

.notify-btn-icon {
  flex-shrink: 0;
  transition: transform var(--duration-fast) var(--ease-out-expo);
}
.notify-btn:hover .notify-btn-icon {
  transform: translateX(3px);
}

.notify-success {
  min-height: 1.4em;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-accent-3);
  letter-spacing: 0.01em;
  margin: 0;
}
.notify-success--dark {
  color: #3b82f6;
}

/* ─── 12. FOOTER ─────────────────────────────────────────── */
.qed-footer {
  background: var(--color-bg);
  border-top: 1px solid var(--color-glass-border);
  padding: var(--space-16) 0 var(--space-10);
}
.footer-inner {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-3);
}
.footer-brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-2);
}
.footer-logo {
  width: 28px;
  height: 28px;
  object-fit: contain;
  filter: brightness(10) opacity(0.7);
}
.footer-wordmark {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-muted);
  letter-spacing: -0.01em;
}
.footer-tagline {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: 0.95rem;
  color: var(--color-muted-2);
}
.footer-meta, .footer-copy {
  font-size: 0.8rem;
  color: var(--color-muted-2);
  letter-spacing: 0.02em;
}