/* ── MVP 共用樣式 ── */
:root {
  --bg:       #0d1117;
  --surface:  #161b22;
  --surface2: #21262d;
  --border:   #30363d;
  --text:     #e6edf3;
  --muted:    #8b949e;
  --accent:   #22d3ee;
  --accent-dk:#0891b2;
  --danger:   #f85149;
  --success:  #3fb950;
  --nav-h:    60px;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'PingFang TC', 'Microsoft JhengHei', 'Noto Sans TC', sans-serif;
  line-height: 1.6;
  min-height: 100vh;
}

a { color: inherit; text-decoration: none; }

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

/* ── Navbar ── */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-h);
  background: rgba(13,17,23,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 5%;
  z-index: 100;
}

.nav-logo {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.04em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-links a {
  font-size: 0.88rem;
  color: var(--muted);
  transition: color 0.2s;
}

.nav-links a:hover { color: var(--text); }

/* 漢堡按鈕 */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 4px;
}

.hamburger span {
  display: block;
  width: 22px; height: 2px;
  background: var(--text);
  transition: transform 0.3s, opacity 0.3s;
  border-radius: 2px;
}

.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* 手機版選單 */
.mobile-menu {
  display: none;
  position: fixed;
  top: var(--nav-h); left: 0; right: 0;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 20px 5%;
  z-index: 99;
  flex-direction: column;
  gap: 0;
}

.mobile-menu.open { display: flex; }

.mobile-menu a {
  padding: 14px 0;
  font-size: 1rem;
  color: var(--muted);
  border-bottom: 1px solid var(--border);
  transition: color 0.2s;
}

.mobile-menu a:last-child { border-bottom: none; }
.mobile-menu a:hover { color: var(--accent); }

/* ── 按鈕 ── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 12px 28px;
  border-radius: 8px;
  font-size: 0.92rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: opacity 0.2s, transform 0.15s;
  text-align: center;
}

.btn:hover { opacity: 0.88; transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

.btn-primary {
  background: var(--accent);
  color: #000;
  width: 100%;
}

.btn-outline {
  background: transparent;
  color: var(--accent);
  border: 1.5px solid var(--accent);
  width: 100%;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

/* ── 表單 ── */
.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 18px;
}

.form-group label {
  font-size: 0.85rem;
  color: var(--muted);
  font-weight: 500;
}

.form-group label .required { color: var(--accent); margin-left: 2px; }

.form-group input,
.form-group select,
.form-group textarea {
  background: var(--surface2);
  border: 1.5px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-size: 0.95rem;
  font-family: inherit;
  padding: 12px 14px;
  transition: border-color 0.2s;
  width: 100%;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--accent);
}

.form-group textarea { resize: vertical; min-height: 90px; }

/* radio group */
.radio-group {
  display: flex;
  gap: 16px;
}

.radio-group label {
  display: flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  color: var(--text);
  font-size: 0.95rem;
  font-weight: 400;
}

.radio-group input[type="radio"] {
  width: 16px; height: 16px;
  accent-color: var(--accent);
}

/* 表單狀態訊息 */
.form-msg {
  display: none;
  padding: 14px 16px;
  border-radius: 8px;
  font-size: 0.9rem;
  margin-top: 16px;
  text-align: center;
}

.form-msg.success {
  display: block;
  background: rgba(63,185,80,0.12);
  border: 1px solid rgba(63,185,80,0.3);
  color: var(--success);
}

.form-msg.error {
  display: block;
  background: rgba(248,81,73,0.12);
  border: 1px solid rgba(248,81,73,0.3);
  color: var(--danger);
}

/* ── 頁尾 ── */
footer {
  border-top: 1px solid var(--border);
  padding: 32px 5%;
  text-align: center;
  color: var(--muted);
  font-size: 0.82rem;
  margin-top: 80px;
}

/* ── RWD ── */
@media (max-width: 767px) {
  .hamburger { display: flex; }
  .nav-links  { display: none; }
}

@media (min-width: 768px) {
  .btn { width: auto; }
}