/* ===== IMPORTS ===== */
@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@400;500;600;700;800;900&family=Nunito:wght@400;500;600;700;800&family=IBM+Plex+Mono:wght@400;600;700&display=swap');
@import url('https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.1/css/all.min.css');

/* ===== CSS VARIABLES ===== */
:root {
  --primary: #005da4;
  --primary-dim: #00518f;
  --primary-container: #4fa4ff;
  --on-primary: #edf3ff;
  --surface: #f5f6ff;
  --surface-container: #dfe8ff;
  --surface-container-low: #ecf0ff;
  --surface-container-lowest: #ffffff;
  --on-surface: #1a2f50;
  --on-surface-variant: #485c80;
  --outline: #63779d;
  --outline-variant: #9aadd6;
  --background: #f5f6ff;
  --secondary: #a83206;
  --tertiary: #7c40a2;
  --error: #b31b25;

  --font-headline: 'Plus Jakarta Sans', sans-serif;
  --font-body: 'Nunito', sans-serif;
  --font-mono: 'IBM Plex Mono', monospace;

  --border-black: 4px solid #000;
  --card-border: 2px solid #000000;
  --transition-base: 0.2s ease;
  --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.05);
  --shadow-card-hover: 0 2px 6px rgba(0, 0, 0, 0.08);
  --shadow-section: 2px 2px 10px 0px rgba(0, 0, 0, 0.05);
  --shadow-hero: 0 8px 32px rgba(0, 60, 140, 0.18);
  --radius: 0rem;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-body);
  background-color: #f0f4ff;
  color: var(--on-surface);
  min-height: 100vh;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120' viewBox='0 0 120 120'%3E%3Cdefs%3E%3Cstyle%3E.t%7Bstroke:%23bfcaf8;stroke-width:1;fill:none%7D.d%7Bfill:%23a5b4fc%7D.c%7Bfill:%23c7d2fe;stroke:%23bfcaf8;stroke-width:0.8%7D%3C/style%3E%3C/defs%3E%3Crect width='120' height='120' fill='%23f0f4ff'/%3E%3Cline class='t' x1='0' y1='60' x2='34' y2='60'/%3E%3Cline class='t' x1='86' y1='60' x2='120' y2='60'/%3E%3Cline class='t' x1='60' y1='0' x2='60' y2='34'/%3E%3Cline class='t' x1='60' y1='86' x2='60' y2='120'/%3E%3Cline class='t' x1='0' y1='20' x2='20' y2='20'/%3E%3Cline class='t' x1='20' y1='20' x2='20' y2='40'/%3E%3Cline class='t' x1='100' y1='80' x2='120' y2='80'/%3E%3Cline class='t' x1='100' y1='80' x2='100' y2='100'/%3E%3Cline class='t' x1='0' y1='100' x2='20' y2='100'/%3E%3Cline class='t' x1='20' y1='100' x2='20' y2='120'/%3E%3Cline class='t' x1='100' y1='0' x2='100' y2='20'/%3E%3Cline class='t' x1='100' y1='20' x2='120' y2='20'/%3E%3Crect class='c' x='34' y='34' width='52' height='52' rx='3'/%3E%3Crect x='44' y='44' width='32' height='32' rx='2' fill='%23dde4fd' stroke='%23a5b4fc' stroke-width='0.8'/%3E%3Crect x='52' y='52' width='16' height='16' rx='1.5' fill='%23c7d2fe'/%3E%3Ccircle class='d' cx='34' cy='60' r='2.5'/%3E%3Ccircle class='d' cx='86' cy='60' r='2.5'/%3E%3Ccircle class='d' cx='60' cy='34' r='2.5'/%3E%3Ccircle class='d' cx='60' cy='86' r='2.5'/%3E%3Ccircle class='d' cx='20' cy='20' r='1.8'/%3E%3Ccircle class='d' cx='100' cy='100' r='1.8'/%3E%3Ccircle class='d' cx='20' cy='100' r='1.8'/%3E%3Ccircle class='d' cx='100' cy='20' r='1.8'/%3E%3C/svg%3E");
  background-size: 120px 120px;
  padding: 3rem 0;
  transition: background-color 0.3s, color 0.3s;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  line-height: 1.7;
  font-size: 16px;
  font-weight: 500;
}

/* ===== BINARY RAIN CANVAS ===== */
#binary-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
  opacity: 0.85;
}

/* ===== SELECTION ===== */
::selection {
  background-color: var(--primary-container);
  color: #002444;
}

/* ===== LAYOUT ===== */
.page-wrapper {
  min-height: 100vh;
  position: relative;
  z-index: 1;
}

.main-container {
  max-width: 1900px;
  margin: 0 auto;
  padding: 0 1rem;
}

@media (min-width: 768px) {
  .main-container {
    padding: 0 2rem;
  }
}

/* ===== FLOATING NAV BUTTONS ===== */
.floating-nav {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 50;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.nav-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 3rem;
  height: 3rem;
  background-color: var(--primary);
  color: #fff;
  border: none;
  border-radius: 9999px;
  cursor: pointer;
  box-shadow: 0 4px 16px rgba(0, 93, 164, 0.35);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  font-size: 1rem;
}

.nav-btn:hover {
  transform: scale(1.1);
  box-shadow: 0 6px 20px rgba(0, 93, 164, 0.45);
}

/* ===== HERO SECTION ===== */
.hero-section {
  background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
  padding: 2.5rem;
  color: #fff;
  text-align: center;
  margin-bottom: 4rem;
  box-shadow: var(--shadow-hero);
  border-radius: var(--radius);
  position: relative;
  overflow: hidden;
}

.hero-section::before {
  content: '';
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(
    45deg,
    rgba(255,255,255,0.03) 0px,
    rgba(255,255,255,0.03) 1px,
    transparent 1px,
    transparent 20px
  );
  pointer-events: none;
}

.hero-inner {
  position: relative;
  z-index: 1;
}

.hero-title-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 1rem;
}

.hero-icon {
  font-size: 1.875rem;
}

.hero-title {
  font-family: var(--font-headline);
  font-size: clamp(1.6rem, 4.5vw, 2.8rem);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.01em;
}

.hero-subtitle {
  font-size: 1.15rem;
  opacity: 0.92;
  margin-bottom: 0.25rem;
  font-weight: 600;
  letter-spacing: 0.01em;
}

.hero-byline {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  opacity: 0.8;
  margin-bottom: 2rem;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.hero-badge {
  background-color: rgba(255, 255, 255, 0.95);
  color: #2563eb;
  padding: 0.5rem 2rem;
  font-weight: 700;
  font-size: 1rem;
  border-radius: var(--radius);
  box-shadow: 0 1px 4px rgba(0,0,0,0.1);
  display: inline-flex;
  align-items: center;
}

.hero-btn {
  background-color: #fff;
  color: #2563eb;
  padding: 0.5rem 2rem;
  font-weight: 700;
  font-size: 1rem;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  box-shadow: 0 1px 4px rgba(0,0,0,0.1);
  transition: background-color var(--transition-base);
  font-family: var(--font-body);
}

.hero-btn:hover {
  background-color: #eff6ff;
}

/* ===== WEEKS CONTAINER ===== */
.weeks-container {
  display: flex;
  flex-direction: column;
  gap: 3rem;
}

/* ===== WEEK BLOCK ===== */
.week-block {
  display: flex;
  border: var(--border-black);
  background-color: var(--surface-container-lowest);
  box-shadow: var(--shadow-section);
}

/* ===== WEEK LABEL (VERTICAL TEXT) ===== */
.week-label-col {
  width: 8rem;
  background-color: var(--surface-container-lowest);
  border-right: var(--border-black);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 3rem 0;
  flex-shrink: 0;
}

.week-label-text {
  writing-mode: vertical-rl;
  transform: rotate(180deg);
  font-family: var(--font-headline);
  font-weight: 900;
  font-size: 3rem;
  letter-spacing: -0.04em;
  text-transform: uppercase;
  color: #000;
  line-height: 1;
}

/* ===== WEEK CONTENT ===== */
.week-content {
  flex: 1;
  padding: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

/* ===== LECTURE CARD ===== */
.lecture-card {
  border: var(--card-border);
  background-color: var(--surface-container-lowest);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2rem;
  box-shadow: var(--shadow-card);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  border-radius: var(--radius);
}

.lecture-card:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-card-hover);
}

@media (min-width: 1024px) {
  .lecture-card {
    flex-direction: row;
  }
}

/* ===== LECTURE NUMBER BADGE ===== */
.lecture-number {
  flex-shrink: 0;
}

.lecture-num-badge {
  background-color: var(--primary);
  color: var(--on-primary);
  width: 3.5rem;
  height: 3.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.5rem;
  font-family: var(--font-headline);
  border-radius: var(--radius);
  flex-shrink: 0;
}

/* ===== LECTURE INFO ===== */
.lecture-info {
  flex: 1;
  text-align: left;
}

.lecture-title {
  font-family: var(--font-headline);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--on-surface);
  margin-bottom: 0.75rem;
  line-height: 1.5;
  letter-spacing: 0.005em;
}

.lecture-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
}

.meta-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.meta-item.chapter {
  color: #c2410c;
}

.meta-item.date {
  color: #1d4ed8;
}

/* ===== WATCH BUTTON ===== */
.watch-btn-wrap {
  flex-shrink: 0;
  width: 100%;
}

@media (min-width: 1024px) {
  .watch-btn-wrap {
    width: auto;
  }
}

.watch-btn {
  width: 100%;
  background-color: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  padding: 0.95rem 2rem;
  font-size: 0.9rem;
  font-weight: 700;
  font-family: var(--font-body);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0, 93, 164, 0.2);
  transition: background-color var(--transition-base), box-shadow var(--transition-base), transform var(--transition-base);
  min-width: 14rem;
  letter-spacing: 0.03em;
  text-decoration: none;
}

@media (min-width: 1024px) {
  .watch-btn {
    width: 14rem;
  }
}

.watch-btn:hover {
  background-color: var(--primary-dim);
  box-shadow: 0 4px 12px rgba(0, 93, 164, 0.3);
  transform: translateY(-1px);
}

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

/* ===== HOLIDAY CARD VARIANT ===== */
.lecture-card--holiday {
  background-color: #fff9f0;
  border-color: #f59e0b;
  opacity: 0.85;
}

.lecture-num-badge--holiday {
  background-color: #f59e0b;
}

.watch-btn--holiday {
  background-color: #f59e0b;
  cursor: pointer;
}

.watch-btn--holiday:hover {
  background-color: #d97706;
}

/* ===== SPACER ===== */
.bottom-spacer {
  height: 0.25rem;
}

/* ===== RESPONSIVE ADJUSTMENTS ===== */
@media (max-width: 640px) {
  .hero-title-row {
    flex-direction: column;
    gap: 0.5rem;
  }

  .hero-icon {
    font-size: 1.5rem;
  }

  .week-label-col {
    width: 3rem;
  }

  .week-label-text {
    font-size: 1.25rem;
  }

  .week-content {
    padding: 1rem;
  }

  .lecture-title {
    font-size: 1.1rem;
  }

  .lecture-meta {
    gap: 0.75rem;
  }
}

@media (max-width: 480px) {
  body {
    padding: 1.5rem 0;
  }

  .hero-section {
    padding: 1.5rem 1rem;
    margin-bottom: 2rem;
  }

  .floating-nav {
    bottom: 1rem;
    right: 1rem;
  }
}