/* ========= Design System — Elegant Academic ========= */
html[lang="en"]{
  --font-heading:'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-body:'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

:root{
  /* Brand Colors – Navy & Maroon, with Gold as a decorative-only accent */
  --primary:#1B3A5C;        /* deep navy */
  --primary-600:#16304C;
  --primary-700:#11253D;
  --accent:#7A2333;         /* deep maroon — used for destructive/attention actions (logout, cancel, delete) */
  --accent-600:#6B1E2C;
  --accent-700:#5C1926;
  --gold:#C9A227;           /* decorative only: top accent bar, brand mark, hero, featured CTA — never semantic */
  --gold-600:#B08F1F;

  /* Neutrals & Surfaces */
  --bg:#F4F6F8;
  --card:#ffffff;
  --ink:#14213D;
  --muted:#5B6472;
  --ring:rgba(27,58,92,.35);

  /* Radii & Shadows */
  --r-lg:20px;
  --r-md:14px;
  --r-sm:12px;
  --shadow-1:0 8px 24px rgba(2,8,23,.06);
  --shadow-2:0 12px 30px rgba(2,8,23,.10);

  /* Gradients */
  --grad:linear-gradient(135deg, var(--primary), #2c5686 60%, var(--gold) 130%);
  --grad-accent:linear-gradient(135deg, var(--primary), var(--gold));
  --grad-brand:linear-gradient(135deg, var(--gold), #e0bf52);

  /* Fonts */
  --font-heading:'Cairo', 'Georgia', serif;
  --font-body:'Cairo', system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Noto Sans", sans-serif;
}

@media (prefers-color-scheme: dark){
  :root{
    --bg:#0B1420;
    --card:#101C2E;
    --ink:#E7ECF5;
    --muted:#94A2B8;
    --shadow-1:0 8px 24px rgba(0,0,0,.35);
    --shadow-2:0 12px 30px rgba(0,0,0,.5);
  }
}

/* ========= Base ========= */
*{box-sizing:border-box}
html,body{height:100%}
body{
  font-family:var(--font-body);
  background:var(--bg);
  color:var(--ink);
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}

h1,h2,h3,h4,h5,h6{font-family:var(--font-heading);font-weight:700}

.container{max-width:1100px;margin:auto;padding:24px}

/* ========= Cards & Surfaces ========= */
.card{
  background:var(--card);
  border:0;
  border-radius:var(--r-lg);
  box-shadow:var(--shadow-1);
  padding:20px;
  transition:transform .25s ease, box-shadow .25s ease;
}
.card:hover{transform:translateY(-4px);box-shadow:var(--shadow-2)}
.glass{
  background:linear-gradient(180deg,rgba(255,255,255,.55),rgba(255,255,255,.35));
  backdrop-filter:blur(10px);
  -webkit-backdrop-filter:blur(10px);
  border:1px solid rgba(255,255,255,.35);
}

/* ========= Buttons ========= */
.btn{appearance:none;border:0;border-radius:var(--r-sm);padding:12px 16px;font-weight:600;cursor:pointer;transition:transform .1s ease, box-shadow .25s ease, background .25s ease}
.btn:active{transform:translateY(1px)}
.btn:focus-visible{outline:0;box-shadow:0 0 0 4px var(--ring)}

.btn-primary{background:var(--primary);color:#fff;box-shadow:0 6px 18px rgba(27,58,92,.25)}
.btn-primary:hover{background:var(--primary-600)}
.btn-primary:active{background:var(--primary-700)}

.btn-accent{background:var(--accent);color:#fff;box-shadow:0 6px 18px rgba(122,35,51,.25)}
.btn-accent:hover{background:var(--accent-600)}
.btn-accent:active{background:var(--accent-700)}

/* Featured/premium CTA (e.g. course reservation) — gold, distinct from primary/accent semantics */
.btn-brand{background:var(--grad-brand);color:#fff;box-shadow:0 6px 18px rgba(201,162,39,.35)}
.btn-brand:hover{filter:brightness(.96)}
.btn-brand:active{filter:brightness(.9)}

.btn-outline{
  background:transparent;color:var(--primary);border:2px solid var(--primary);
}
.btn-outline:hover{background:color-mix(in srgb, var(--primary) 8%, transparent)}

/* ========= Badges ========= */
.badge{display:inline-flex;align-items:center;gap:8px;font-weight:600;border-radius:999px;padding:6px 10px;font-size:.85rem}
.badge-soft{background:color-mix(in srgb, var(--primary) 12%, white);color:var(--primary-700)}
.badge-danger{background:color-mix(in srgb, var(--accent) 12%, white);color:var(--accent-700)}
.badge-success{background:linear-gradient(135deg,#10b981,#059669);color:#fff}
.badge-warning{background:linear-gradient(135deg,#f59e0b,#d97706);color:#fff}

/* ========= Page header ========= */
.page-header{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:12px;margin-bottom:16px}
.page-header h4,.page-header h5{margin:0}

/* ========= Empty state ========= */
.empty-state{text-align:center;padding:32px 16px;color:var(--muted)}
.empty-state .icon{font-size:28px;margin-bottom:8px}

/* ========= Hero ========= */
.hero{
  background:var(--grad);
  color:#fff;
  border-radius:var(--r-lg);
  padding:32px;
  position:relative;
  overflow:hidden;
  box-shadow:var(--shadow-2);
}
.hero h1{margin:0 0 8px;font-size:clamp(24px,3vw,36px);font-weight:800;letter-spacing:.2px}
.hero p{opacity:.95;margin:0}
.hero::after{
  content:"";
  position:absolute;inset:auto -20% -40% -20%;
  height:140%;
  background:radial-gradient(closest-side,rgba(255,255,255,.25),transparent 70%);
  animation:float 6s ease-in-out infinite;
}

/* ========= Course Card (example hover) ========= */
.course-card{transition:transform .25s ease, box-shadow .25s ease}
.course-card:hover{transform:translateY(-6px) scale(1.01);box-shadow:var(--shadow-2)}

/* ========= Tables ========= */
.table{
  width:100%;
  border-collapse:separate;
  border-spacing:0;
  background:var(--card);
  border-radius:var(--r-md);
  overflow:hidden;
  box-shadow:var(--shadow-1);
}
.table thead th{
  background:color-mix(in srgb, var(--primary) 10%, transparent);
  text-align:start;
  padding:14px; font-weight:700; color:var(--primary-700);
}
.table tbody td{padding:14px;border-top:1px solid rgba(2,8,23,.06)}
.table tbody tr:hover{background:color-mix(in srgb, var(--primary) 5%, transparent)}

/* ========= Forms ========= */
.input, select, textarea{
  width:100%;padding:12px 14px;border-radius:12px;border:1.5px solid rgba(2,8,23,.1);
  background:#fff;color:var(--ink);transition:border .2s ease, box-shadow .2s ease, background .2s ease;
}
.input::placeholder{color:#94a3b8}
.input:focus, select:focus, textarea:focus{outline:0;border-color:var(--primary);box-shadow:0 0 0 4px var(--ring)}

.input-danger{border-color:var(--accent)}
.input-danger:focus{box-shadow:0 0 0 4px color-mix(in srgb, var(--accent) 25%, transparent)}

/* ========= Nav (underline animation) ========= */
.nav{
  display:flex;gap:18px;flex-wrap:wrap
}
.nav a{
  position:relative;text-decoration:none;color:var(--muted);font-weight:700;padding:8px 2px
}
.nav a::after{
  content:"";position:absolute;left:0;right:100%;bottom:0;height:3px;border-radius:3px;background:var(--grad-accent);
  transition:right .25s ease
}
.nav a:hover{color:var(--ink)}
.nav a:hover::after{right:0}

/* ========= Shared topbar (student/admin/teacher layouts) ========= */
.top-accent{height:4px;background:var(--grad-accent)}
.navbar-glass{
  background:linear-gradient(180deg, var(--primary-700), var(--primary));
  box-shadow:0 8px 24px rgba(2,8,23,.25);
  border-bottom:1px solid rgba(255,255,255,.08);
}
.brand-mark{
  font-family:var(--font-heading);
  font-weight:700; letter-spacing:.2px;
  background:var(--grad-brand);
  -webkit-background-clip:text; background-clip:text; color:transparent;
}
.navbar .nav-link{
  position:relative; font-weight:700; color:rgba(255,255,255,.75);
}
.navbar .nav-link:hover,.navbar .nav-link.active{color:#fff}
.navbar-expand-lg .navbar-toggler{border-color:rgba(255,255,255,.25)}
.navbar-account-link{color:rgba(255,255,255,.8);text-decoration:none}
.navbar-account-link:hover{color:#fff}
.offcanvas{background:var(--primary-700);color:#fff}
.offcanvas .nav-link{padding:10px 4px;color:rgba(255,255,255,.75)}
.offcanvas .nav-link:hover,.offcanvas .nav-link.active{color:#fff}
.offcanvas-header{border-bottom:1px solid rgba(255,255,255,.12)}
.offcanvas hr{border-color:rgba(255,255,255,.15)}

/* ========= Icon cards (KPIs / categories) ========= */
.icon-card{
  background:var(--card);
  border-radius:var(--r-md);
  padding:16px 18px;
  display:flex;align-items:center;gap:14px;
  box-shadow:var(--shadow-1);
  transition:transform .25s ease, box-shadow .25s ease;
}
.icon-card:hover{transform:translateY(-3px);box-shadow:var(--shadow-2)}
.icon-card .num{font-size:26px;font-weight:800}
.icon-card .label{color:var(--muted);font-size:.9rem}
.icon-box{
  width:52px;height:52px;border-radius:14px;flex-shrink:0;
  display:flex;align-items:center;justify-content:center;
  font-size:22px;color:#fff;
  background:linear-gradient(135deg, var(--primary), var(--primary-600));
}

/* ========= Animations ========= */
@keyframes float{
  0%,100%{transform:translateY(0) rotate(0)}
  50%{transform:translateY(-10px) rotate(1deg)}
}
@keyframes fadeInUp{
  from{opacity:0;transform:translateY(16px)}
  to{opacity:1;transform:translateY(0)}
}
@keyframes shimmer{
  0%{background-position:-200% 0}
  100%{background-position:200% 0}
}

/* Utilities */
.fade-in-up{animation:fadeInUp .6s ease both}
.float{animation:float 5s ease-in-out infinite}
.pulse{
  box-shadow:0 0 0 0 var(--ring);
  animation:pulseRing 2s infinite
}
@keyframes pulseRing{
  0%{box-shadow:0 0 0 0 var(--ring)}
  70%{box-shadow:0 0 0 16px rgba(27,58,92,0)}
  100%{box-shadow:0 0 0 0 rgba(27,58,92,0)}
}

/* Skeleton loader */
.skeleton{
  border-radius:12px; height:14px;
  background:linear-gradient(90deg, rgba(2,8,23,.06), rgba(2,8,23,.12), rgba(2,8,23,.06));
  background-size:200% 100%; animation:shimmer 1.5s linear infinite;
}

/* Reduce motion respect */
@media (prefers-reduced-motion:reduce){
  *{animation:none!important;transition:none!important}
}