/* =====================================================
   AG102 GLOBAL DESIGN SYSTEM — Light Theme
   =====================================================
   This stylesheet provides the shared nav bar, layout,
   typography, and color system for the new light theme.
   It does NOT replace styles.css — old pages continue
   to use styles.css + exercise.css as before.
   ===================================================== */

/* ── COLOR SYSTEM ── */
:root {
  /* Page backgrounds */
  --ag-bg: #F5F0EB;
  --ag-bg-alt: #FAF7F4;
  --ag-surface: #FFFFFF;

  /* Text */
  --ag-text: #2D1B14;
  --ag-text-muted: #7A6B63;
  --ag-text-light: #A89B93;

  /* Brand colors */
  --ag-primary: #8B4513;
  --ag-primary-hover: #7A3A10;
  --ag-accent: #B85042;
  --ag-success: #4A7C59;
  --ag-warning: #D4A574;
  --ag-info: #4A90D9;

  /* Nav bar (dark for contrast) */
  --ag-nav-bg: #0B1120;
  --ag-nav-text: #C0B8B0;
  --ag-nav-hover: rgba(255,255,255,0.08);
  --ag-nav-active-text: #FFFFFF;
  --ag-nav-active-bg: #8B4513;

  /* Borders & shadows */
  --ag-border: #E5E0DB;
  --ag-shadow: 0 2px 8px rgba(45, 27, 20, 0.08);
  --ag-shadow-lg: 0 4px 16px rgba(45, 27, 20, 0.12);

  /* Border radius */
  --ag-radius-sm: 6px;
  --ag-radius-md: 10px;
  --ag-radius-lg: 16px;
}

/* ── DARK THEME OVERRIDES ── */
html.theme-dark {
  /* Page backgrounds */
  --ag-bg: #0f0f23;
  --ag-bg-alt: #141829;
  --ag-surface: #1a1f2e;

  /* Text */
  --ag-text: #ffffff;
  --ag-text-muted: rgba(255,255,255,0.5);
  --ag-text-light: rgba(255,255,255,0.3);

  /* Brand — restore original green/gold */
  --ag-primary: #2D5A3D;
  --ag-primary-hover: #3A6D4C;
  --ag-accent: #D4A84B;
  --ag-success: #4A7C59;
  --ag-warning: #D4A84B;
  --ag-info: #4A90D9;

  /* Nav bar (stays dark in both themes) */
  --ag-nav-active-bg: #2D5A3D;

  /* Borders & shadows */
  --ag-border: rgba(255,255,255,0.1);
  --ag-shadow: 0 2px 8px rgba(0,0,0,0.3);
  --ag-shadow-lg: 0 4px 16px rgba(0,0,0,0.4);

  /* muscle-explorer.css additional vars */
  --ag-cream: #0f0f23;
  --ag-card: rgba(255,255,255,0.08);
  --ag-dark: #E8E0D8;
  --ag-muted: rgba(255,255,255,0.5);
}

/* ── RESET (scoped to pages that use this file) ── */
*, *::before, *::after { box-sizing: border-box; }

/* =====================================================
   NAVIGATION BAR
   ===================================================== */

.site-nav {
  display: flex;
  align-items: center;
  background: var(--ag-nav-bg);
  padding: 0 24px;
  height: 56px;
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid rgba(255,255,255,0.06);
}

/* Logo */
.nav-logo {
  margin-right: 32px;
  flex-shrink: 0;
}

.nav-logo a {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.nav-logo-img {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  object-fit: contain;
  background: rgba(255,255,255,0.95);
  padding: 2px;
}

.nav-logo-text {
  display: flex;
  flex-direction: column;
}

.nav-logo-title {
  font-size: 14px;
  font-weight: 700;
  color: #fff;
  line-height: 1.2;
}

.nav-logo-num {
  color: var(--ag-warning);
  margin-left: 1px;
}

.nav-logo-tagline {
  font-size: 10px;
  color: #6B7280;
  font-weight: 400;
}

/* Nav links container */
.site-nav .nav-links {
  display: flex;
  gap: 4px;
  flex: 1;
  align-items: center;
}

.site-nav .nav-link {
  color: var(--ag-nav-text);
  text-decoration: none;
  padding: 6px 14px;
  border-radius: var(--ag-radius-sm);
  font-size: 14px;
  white-space: nowrap;
  transition: background 0.2s, color 0.2s;
  display: flex;
  align-items: center;
  min-height: 36px;
}

.site-nav .nav-link:hover {
  background: var(--ag-nav-hover);
  color: #fff;
}

.site-nav .nav-link.active {
  background: var(--ag-nav-active-bg);
  color: var(--ag-nav-active-text);
  font-weight: 600;
}

/* Premium badge */
.site-nav .premium-badge {
  background: var(--ag-warning);
  color: var(--ag-nav-bg);
  font-size: 9px;
  font-weight: 700;
  padding: 2px 6px;
  border-radius: 3px;
  margin-left: 6px;
  vertical-align: middle;
  text-transform: uppercase;
}

/* User section */
.site-nav .nav-user-section {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-left: auto;
  flex-shrink: 0;
}

.site-nav .nav-guest {
  display: flex;
  align-items: center;
  gap: 8px;
}

.site-nav .nav-guest.hidden {
  display: none;
}

.site-nav .btn-nav-login {
  color: var(--ag-nav-text);
  text-decoration: none;
  padding: 6px 14px;
  border-radius: var(--ag-radius-sm);
  font-size: 14px;
  transition: all 0.2s;
}

.site-nav .btn-nav-login:hover {
  color: #fff;
  background: rgba(255,255,255,0.05);
}

.site-nav .btn-nav-signup {
  background: var(--ag-primary);
  color: white;
  text-decoration: none;
  padding: 6px 14px;
  border-radius: var(--ag-radius-sm);
  font-weight: 600;
  font-size: 14px;
  transition: all 0.2s;
}

.site-nav .btn-nav-signup:hover {
  background: var(--ag-primary-hover);
}

/* User menu (logged in) */
.site-nav .nav-user {
  display: flex;
  align-items: center;
  gap: 8px;
  position: relative;
}

.site-nav .nav-user.hidden {
  display: none;
}

.site-nav .user-tier-badge {
  background: var(--ag-warning);
  color: #000;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
}

.site-nav .user-tier-badge:not(.premium) {
  display: none;
}

.site-nav .user-menu-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 8px;
  padding: 6px 12px;
  color: #fff;
  cursor: pointer;
  font-size: 14px;
  transition: all 0.2s;
}

.site-nav .user-menu-btn:hover,
.site-nav .user-menu-btn.active {
  background: rgba(255,255,255,0.1);
  border-color: var(--ag-primary);
}

.site-nav .user-menu-btn .chevron {
  width: 12px;
  height: 12px;
  transition: transform 0.2s;
}

.site-nav .user-menu-btn.active .chevron {
  transform: rotate(180deg);
}

.site-nav .user-dropdown {
  position: absolute;
  top: 100%;
  right: 0;
  margin-top: 8px;
  background: #1a1f2e;
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 8px;
  min-width: 180px;
  padding: 6px 0;
  box-shadow: 0 4px 16px rgba(0,0,0,0.4);
  z-index: 1000;
}

.site-nav .user-dropdown.hidden {
  display: none;
}

.site-nav .user-dropdown a,
.site-nav .user-dropdown button {
  display: block;
  width: 100%;
  padding: 8px 16px;
  color: var(--ag-nav-text);
  text-decoration: none;
  text-align: left;
  background: none;
  border: none;
  cursor: pointer;
  font-size: 14px;
  transition: all 0.15s;
}

.site-nav .user-dropdown a:hover,
.site-nav .user-dropdown button:hover {
  background: rgba(255,255,255,0.05);
  color: #fff;
}

.site-nav .user-dropdown hr {
  border: none;
  border-top: 1px solid rgba(255,255,255,0.1);
  margin: 4px 0;
}

.site-nav .user-dropdown .upgrade-link {
  color: var(--ag-warning);
}

.site-nav .user-dropdown .upgrade-link:hover {
  background: rgba(212, 165, 116, 0.1);
}

/* Theme toggle button */
.site-nav .theme-toggle-btn {
  background: transparent;
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: var(--ag-radius-sm);
  padding: 6px;
  cursor: pointer;
  color: var(--ag-nav-text);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
  flex-shrink: 0;
}

.site-nav .theme-toggle-btn:hover {
  background: rgba(255,255,255,0.08);
  color: #fff;
}

.site-nav .theme-toggle-btn svg {
  width: 18px;
  height: 18px;
}

/* =====================================================
   MOBILE NAV
   ===================================================== */

@media (max-width: 900px) {
  .site-nav {
    flex-wrap: wrap;
    height: auto;
    padding: 8px 16px;
    gap: 4px;
  }

  .nav-logo {
    margin-right: auto;
  }

  .site-nav .nav-links {
    order: 3;
    width: 100%;
    overflow-x: auto;
    padding-top: 8px;
    gap: 2px;
    -webkit-overflow-scrolling: touch;
  }

  .site-nav .nav-link {
    font-size: 13px;
    padding: 6px 10px;
  }

  .site-nav .nav-user-section {
    order: 2;
  }
}

@media (max-width: 480px) {
  .nav-logo-text {
    display: none;
  }
}