/* ===== Common Styles - Usolveplay ===== */

:root {
    --bg-primary: #0a0e1a;
    --bg-secondary: #111827;
    --bg-card: #1a2035;
    --bg-input: #1e2940;
    --accent: #6c5ce7;
    --accent-light: #a78bfa;
    --accent-glow: rgba(108, 92, 231, 0.3);
    --accent-glow-strong: rgba(108, 92, 231, 0.5);
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --gradient-1: linear-gradient(135deg, #6c5ce7, #a78bfa);
    --gradient-2: linear-gradient(135deg, #f093fb, #f5576c);
    --gradient-3: linear-gradient(135deg, #4facfe, #00f2fe);
    --border: rgba(108, 92, 231, 0.15);
    --gold: #ffdd2e;
    --green: #10b981;
    --green-glow: rgba(16, 185, 129, 0.25);
    --red: #f5576c;
    --red-glow: rgba(245, 86, 108, 0.25);
    --tip: #ffdd2e;
    --error: #F44336;
}

* {
  margin: 0; padding: 0; box-sizing: border-box;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  min-height: 100vh;
}

.container { margin: 0 auto; }

/* ===== Header ===== */
.header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(10, 14, 26, 0.9);
  backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  padding: 12px 16px;
  display: flex; align-items: center; gap: 12px;
}

.back-btn {
  width: 36px; height: 36px; border-radius: 12px;
  border: 1px solid var(--border); background: var(--bg-card);
  color: var(--text-primary); cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: all 0.3s; text-decoration: none;
}

.back-btn:hover { background: var(--accent); border-color: var(--accent); }

.header-title { font-size: 16px; font-weight: 600; flex: 1; }

.header-title span {
  background: var(--gradient-1);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}

/* ===== Footer ===== */
.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
}

.footer-links { display: flex; gap: 20px; }

.footer-links a {
  color: var(--text-secondary); text-decoration: none;
  font-size: 13px; transition: color 0.3s;
}

.footer-links a:hover { color: var(--accent-light); }

.footer-copy { font-size: 12px; color: var(--text-muted); }

/* ===== Back to Top ===== */
.back-top {
  position: fixed; bottom: 24px; right: 20px;
  width: 40px; height: 40px; border-radius: 50%;
  background: var(--accent); border: none; color: #fff;
  cursor: pointer; display: none;
  align-items: center; justify-content: center;
  box-shadow: 0 4px 15px var(--accent-glow);
  transition: all 0.3s; z-index: 50;
}

.back-top.show { display: flex; }

.back-top:hover { transform: translateY(-2px); }

/* ===== Page Hero ===== */
.page-hero {
  padding: 32px 20px 24px; text-align: center; position: relative;
}

.page-hero::after {
  content: ''; position: absolute; bottom: 0; left: 20px; right: 20px;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
  opacity: 0.3;
}

.page-hero h1 {
  font-size: 28px; font-weight: 800; margin-bottom: 8px;
}

.page-hero .subtitle { font-size: 13px; color: var(--text-muted); }

/* ===== Content ===== */
.content { padding: 24px 20px 40px; }

/* ===== Article ===== */
.article { margin-bottom: 28px; }

.article-header {
  display: flex; align-items: center; gap: 10px;
  margin-bottom: 14px;
}

.article-title { font-size: 17px; font-weight: 700; }

.article-body p {
  font-size: 14px; color: var(--text-secondary);
  margin-bottom: 12px; line-height: 1.8;
}

.article-body p:last-child { margin-bottom: 0; }

.article-body ul {
  list-style: none; padding: 0; margin: 0 0 12px;
}

.article-body ul li {
  position: relative;
  padding: 8px 12px 8px 24px;
  font-size: 14px; color: var(--text-secondary); line-height: 1.7;
}

.article-body ul li::before {
  content: ''; position: absolute; left: 8px; top: 16px;
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--accent);
}

/* ===== Animations ===== */
@keyframes spin { to { transform: rotate(360deg); } }

/* ===== Responsive (shared) ===== */
@media (min-width: 768px) {
  .page-hero h1 { font-size: 32px; }
  .content { padding: 32px 40px 48px; }
}