/* Svetlá téma - základné premenné */
:root {
  --bg: #ffffff;
  --text: #111111;
  --muted: #6b7280;
  --black: #000000;
  --white: #ffffff;

  --accent: #2e7d32;
  --blue: #1e88e5;
  --orange: #ff9800;
  --shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
  --radius: 12px;
}

/* Tmavá téma */
:root[data-theme="dark"] {
  --bg: #0c0d0f;
  --text: #f3f4f6;
  --muted: #9ca3af;
  --black: #000000;
  --white: #ffffff;

  --accent: #4caf50;
  --blue: #2196f3;
  --orange: #ffb74d;
}

* { box-sizing: border-box; }
html, body {
  margin: 0;
  padding: 0;
}
body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji","Segoe UI Emoji";
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  gap: 16px;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  background: linear-gradient(90deg, var(--accent), var(--blue));
  color: var(--white);
  box-shadow: var(--shadow);
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--white);
  text-decoration: none;
  font-weight: 700;
  letter-spacing: .2px;
}
.logo-mark {
  filter: drop-shadow(0 2px 4px rgba(0, 0, 0, .25));
}
.logo-text {
  font-size: 18px;
}
.site-nav {
  display: flex;
  gap: 16px;
}
.site-nav a {
  color: var(--white);
  text-decoration: none;
  font-weight: 600;
  opacity: .9;
  border-bottom: 2px solid transparent;
  padding-bottom: 4px;
}
.site-nav a[aria-current="page"], .site-nav a:hover {
  border-color: var(--white);
  opacity: 1;
}
.controls {
  display: flex;
  gap: 8px;
}

/* Buttons */
.btn {
  --bgc: var(--accent);
  --c: #fff;
  appearance: none;
  border: none;
  background: var(--bgc);
  color: var(--c);
  padding: 10px 14px;
  border-radius: 10px;
  cursor: pointer;
  font-weight: 700;
  box-shadow: var(--shadow);
  transition: .2s transform ease, .2s opacity ease;
}
.btn:hover { transform: translateY(-1px); }
.btn:active { transform: translateY(0); }
.btn.primary { --bgc: var(--accent); }
.btn.secondary { --bgc: var(--blue); }
.btn.link { --bgc: transparent; --c: var(--accent); box-shadow: none; border: 2px solid var(--accent); }
.btn.danger { --bgc: var(--orange); }
.btn.ghost { --bgc: rgba(255, 255, 255, .2); --c: #fff; }

/* Hero */
.hero {
  margin-top: 20px;
  background: linear-gradient(180deg, rgba(46, 125, 50, .12), transparent 60%);
  border-radius: var(--radius);
  padding: 30px;
  box-shadow: var(--shadow);
}
.hero h1 { font-size: clamp(28px, 4vw, 42px); }
.hero .accent { color: var(--accent); }
.cta-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 10px;
}

/* Grid & Cards */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  margin-top: 24px;
}
.card {
  background: var(--white);
  color: #111;
  border-radius: var(--radius);
  padding: 18px;
  box-shadow: var(--shadow);
  border: 1px solid rgba(0, 0, 0, .06);
}
:root[data-theme="dark"] .card {
  background: #14161a;
  color: #e5e7eb;
  border-color: #222;
}
.card h2 { margin-top: 0; }

/* Footer */
.site-footer {
  padding: 24px;
  text-align: center;
  color: var(--muted);
}

/* ChatGPT widget */
#gpt-box {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 300px;
  background: var(--white);
  border: 1px solid #ccc;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
  font-family: sans-serif;
  z-index: 9999;
}
#gpt-messages {
  max-height: 250px;
  overflow-y: auto;
  padding: 10px;
}
#gpt-input {
  flex: 1;
  padding: 8px;
  border: none;
  outline: none;
}
#gpt-box div:last-child {
  display: flex;
  border-top: 1px solid #ccc;
}
#gpt-box button {
  padding: 8px;
  background: var(--accent);
  color: white;
  border: none;
  cursor: pointer;
}
.msg {
  margin: 8px 0;
  padding: 8px;
  border-radius: 6px;
  white-space: pre-wrap;
}
.msg.user {
  background: #d1e7dd;
  text-align: right;
}
.msg.bot {
  background: #e2e3e5;
  text-align: left;
}