/* ============================================
   สื่อการเรียน Neural Network — สไตล์ร่วม
   ============================================ */
@import url('https://fonts.googleapis.com/css2?family=Sarabun:wght@300;400;600;700;800&family=Kanit:wght@500;700&display=swap');

:root {
  --bg: #0f1226;
  --bg-2: #161a3a;
  --card: #1e2247;
  --card-2: #262b55;
  --primary: #7c5cff;
  --primary-2: #5b3df0;
  --accent: #ff6ec7;
  --good: #34d399;
  --warn: #fbbf24;
  --bad: #f87171;
  --text: #f3f4ff;
  --text-dim: #a5a9d6;
  --border: #2e3370;
  --pos: #60a5fa;
  --neg: #f87171;
}

* { box-sizing: border-box; }
html, body {
  margin: 0;
  padding: 0;
  background:
    radial-gradient(circle at 10% 10%, #2a1a5a 0%, transparent 40%),
    radial-gradient(circle at 90% 80%, #5b1a4a 0%, transparent 40%),
    var(--bg);
  color: var(--text);
  font-family: 'Sarabun', sans-serif;
  min-height: 100vh;
}

h1, h2, h3 { font-family: 'Kanit', sans-serif; margin: 0 0 12px 0; }
h1 { font-size: 2.2rem; }
h2 { font-size: 1.4rem; color: #fff; }
h3 { font-size: 1.1rem; color: var(--text-dim); }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 24px;
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 24px;
  background: rgba(20, 22, 60, 0.6);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.topbar .logo {
  font-family: 'Kanit', sans-serif;
  font-weight: 700;
  font-size: 1.2rem;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.topbar nav a {
  color: var(--text);
  margin-left: 18px;
  font-weight: 600;
  opacity: 0.7;
  transition: opacity 0.2s;
}
.topbar nav a:hover, .topbar nav a.active { opacity: 1; text-decoration: none; }
.topbar nav a.active { color: var(--accent); }

.card {
  background: linear-gradient(180deg, var(--card), var(--card-2));
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 20px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.35);
}

.btn {
  background: linear-gradient(90deg, var(--primary), var(--primary-2));
  color: #fff;
  border: none;
  padding: 10px 18px;
  border-radius: 10px;
  font-family: 'Kanit', sans-serif;
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: transform 0.1s, filter 0.2s;
}
.btn:hover { filter: brightness(1.15); }
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }
.btn.secondary { background: var(--card-2); border: 1px solid var(--border); }
.btn.danger    { background: linear-gradient(90deg, #ef4444, #b91c1c); }
.btn.success   { background: linear-gradient(90deg, #10b981, #059669); }

.btn-group { display: inline-flex; gap: 0; border-radius: 10px; overflow: hidden; border: 1px solid var(--border); }
.btn-group button {
  background: var(--card-2);
  color: var(--text-dim);
  border: none;
  padding: 8px 14px;
  font-family: 'Kanit', sans-serif;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}
.btn-group button:hover { background: #303778; color: #fff; }
.btn-group button.active {
  background: linear-gradient(90deg, var(--primary), var(--primary-2));
  color: #fff;
}

label { font-weight: 600; color: var(--text-dim); display: block; margin-bottom: 6px; }
input[type="range"] { width: 100%; }
input[type="number"], select {
  background: var(--card-2);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 10px;
  font-family: inherit;
}

.row { display: flex; gap: 16px; flex-wrap: wrap; }
.col { flex: 1; min-width: 0; }

.stat {
  display: flex;
  flex-direction: column;
  background: var(--card-2);
  padding: 12px 16px;
  border-radius: 10px;
  border: 1px solid var(--border);
}
.stat .label { font-size: 0.8rem; color: var(--text-dim); margin-bottom: 4px; }
.stat .value { font-family: 'Kanit', sans-serif; font-size: 1.4rem; color: #fff; }

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

.help {
  background: rgba(124, 92, 255, 0.1);
  border-left: 4px solid var(--primary);
  padding: 12px 16px;
  border-radius: 8px;
  font-size: 0.92rem;
  color: var(--text-dim);
  line-height: 1.6;
}
.help b { color: var(--text); }

.hero {
  text-align: center;
  padding: 60px 20px 40px;
}
.hero h1 {
  font-size: 3rem;
  background: linear-gradient(90deg, #fff, var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero p { color: var(--text-dim); font-size: 1.15rem; max-width: 700px; margin: 12px auto; }

.menu-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
  margin-top: 30px;
}
.menu-card {
  background: linear-gradient(180deg, var(--card), var(--card-2));
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 28px;
  text-decoration: none;
  color: var(--text);
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
  display: block;
}
.menu-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 16px 48px rgba(124, 92, 255, 0.3);
  border-color: var(--primary);
  text-decoration: none;
}
.menu-card .emoji { font-size: 3.5rem; margin-bottom: 10px; display: block; }
.menu-card h2 { color: #fff; margin-bottom: 8px; }
.menu-card p  { color: var(--text-dim); line-height: 1.6; }
.menu-card .tag {
  display: inline-block;
  background: rgba(124, 92, 255, 0.2);
  color: var(--accent);
  padding: 4px 10px;
  border-radius: 99px;
  font-size: 0.75rem;
  font-weight: 700;
  margin-top: 10px;
}