*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #0e0e0f;
  --surface:   #17181a;
  --border:    #2a2b2e;
  --accent:    #c8f135;
  --accent-dim:#8aaa1f;
  --text:      #f5f5f3;
  --muted:     #a0a2a8;
  --radius:    8px;
}

[lang-vi] h1 {
  font-family: 'Be Vietnam Pro', sans-serif;
  font-weight: 800;
}

[lang-vi], [lang-vi] * {
  font-family: 'Be Vietnam Pro', sans-serif;
  font-size: 15px;
  line-height: 1.9;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'DM Mono', monospace;
  font-size: 15px;
  line-height: 1.8;
  padding: 0;
}

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

.site-header {
  border-bottom: 1px solid var(--border);
  padding: 20px 40px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.logo { display: flex; align-items: center; gap: 10px; }
.logo-icon { color: var(--accent); font-size: 22px; }
.logo-text { font-family: 'Syne', sans-serif; font-size: 22px; font-weight: 800; }
.tagline { font-size: 11px; color: var(--muted); }

.lang-switch { display: flex; gap: 8px; }
.lang-btn {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--muted);
  padding: 5px 12px;
  border-radius: var(--radius);
  cursor: pointer;
  font-family: 'DM Mono', monospace;
  font-size: 12px;
  transition: all 0.2s;
}
.lang-btn.active, .lang-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

main { max-width: 780px; margin: 0 auto; padding: 48px 24px 80px; }

.hero { text-align: center; margin-bottom: 56px; }
.hero h1 { font-family: 'Syne', sans-serif; font-size: 40px; font-weight: 800; line-height: 1.15; margin-bottom: 14px; }
.hero h1 span { color: var(--accent); }
.hero p { color: var(--muted); font-size: 15px; max-width: 500px; margin: 0 auto; }

.section { margin-bottom: 48px; }
.section h2 {
  font-family: 'Syne', sans-serif;
  font-size: 20px;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 20px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

.step {
  display: flex;
  gap: 18px;
  margin-bottom: 24px;
  align-items: flex-start;
}
.step-num {
  flex-shrink: 0;
  width: 32px; height: 32px;
  background: var(--accent);
  color: #0e0e0f;
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-family: 'Syne', sans-serif;
  font-weight: 800;
  font-size: 14px;
}
.step-body h3 { font-size: 16px; font-weight: 600; margin-bottom: 6px; }
.step-body p { color: var(--muted); font-size: 15px; }

.platforms {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 10px;
  margin-top: 8px;
}
.platform-tag {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 8px 12px;
  font-size: 13px;
  text-align: center;
  color: var(--text);
}

.tip {
  background: var(--surface);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 12px 16px;
  font-size: 15px;
  color: var(--muted);
  margin-top: 16px;
}
.tip strong { color: var(--text); }

footer {
  border-top: 1px solid var(--border);
  padding: 24px 40px;
  text-align: center;
  font-size: 13px;
  color: var(--muted);
}
footer a { color: var(--accent); }