/* ============================================
   AI 趨勢說明會 Landing Page
   版型還原參考站：長圖堆疊 + 報名表單 + 返回頂端
   ============================================ */

:root {
  --bg: #020923;            /* 與圖片邊緣背景一致的深海軍藍 */
  --panel: #0a1330;
  --panel-border: #1e2d5c;
  --text: #e8ecf7;
  --text-dim: #9aa5c4;
  --gold: #d8b46a;
  --gold-bright: #f0cd85;
  --error: #ff7a7a;
  --success: #7ce3a1;
  --content-width: 750px;
}

* { box-sizing: border-box; }

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", "微軟正黑體", system-ui, -apple-system, sans-serif;
  -webkit-font-smoothing: antialiased;
}

/* 螢幕閱讀器與搜尋引擎可讀、視覺上隱藏 */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

main {
  max-width: var(--content-width);
  margin: 0 auto;
}

/* ---- 內容長圖：滿版堆疊、無縫相接 ---- */
.block {
  margin: 0;
  line-height: 0; /* 消除圖片間的行高縫隙 */
}

.block img {
  width: 100%;
  height: auto;
  display: block;
}

/* ---- 報名表單 ---- */
.form-section {
  padding: 40px 24px 56px;
  background: var(--bg);
}

.form-heading {
  margin: 0 0 24px;
  text-align: center;
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--gold-bright);
}

#register-form {
  max-width: 560px;
  margin: 0 auto;
}

.field { margin-bottom: 20px; }

.field label {
  display: block;
  margin-bottom: 8px;
  font-size: 1rem;
  font-weight: 500;
  color: var(--text);
}

.req { color: var(--error); }

.field input,
.field select,
.field textarea {
  width: 100%;
  padding: 12px 14px;
  font-size: 1rem;
  font-family: inherit;
  color: var(--text);
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 8px;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.field select { cursor: pointer; }
.field select option { background: var(--panel); color: var(--text); }

.field textarea { resize: vertical; min-height: 96px; line-height: 1.6; }

.field input:focus,
.field select:focus,
.field textarea:focus {
  outline: none;
  border-color: var(--gold);
  box-shadow: 0 0 0 3px rgba(216, 180, 106, 0.18);
}

.field input.invalid,
.field select.invalid {
  border-color: var(--error);
}

.field-error {
  margin: 6px 0 0;
  font-size: 0.875rem;
  color: var(--error);
}

/* 蜜罐欄位：移出視野（勿用 display:none，部分機器人會跳過） */
.hp-field {
  position: absolute;
  left: -9999px;
  top: -9999px;
  height: 1px;
  width: 1px;
  overflow: hidden;
}

#submit-btn {
  display: block;
  width: 100%;
  margin-top: 28px;
  padding: 15px 20px;
  font-size: 1.15rem;
  font-weight: 700;
  font-family: inherit;
  letter-spacing: 0.35em;
  text-indent: 0.35em;
  color: #1b1403;
  background: linear-gradient(135deg, var(--gold-bright), var(--gold));
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.2s, opacity 0.2s;
  box-shadow: 0 4px 18px rgba(216, 180, 106, 0.25);
}

#submit-btn:hover { transform: translateY(-2px); box-shadow: 0 6px 24px rgba(216, 180, 106, 0.4); }
#submit-btn:active { transform: translateY(0); }
#submit-btn:disabled { opacity: 0.6; cursor: not-allowed; transform: none; }

.form-status {
  margin: 18px 0 0;
  padding: 14px 16px;
  border-radius: 8px;
  font-size: 1rem;
  line-height: 1.6;
  text-align: center;
}

/* 空狀態時收合但保留在無障礙樹中，訊息注入時螢幕閱讀器才會播報 */
.form-status:empty {
  margin: 0;
  padding: 0;
  border: none;
}

.form-status.ok {
  color: var(--success);
  background: rgba(124, 227, 161, 0.08);
  border: 1px solid rgba(124, 227, 161, 0.35);
}

.form-status.fail {
  color: var(--error);
  background: rgba(255, 122, 122, 0.08);
  border: 1px solid rgba(255, 122, 122, 0.35);
}

/* ---- 頁尾 ---- */
.site-footer {
  padding: 24px 0 40px;
  text-align: center;
  border-top: 1px solid var(--panel-border);
}

#back-to-top {
  color: var(--text-dim);
  font-size: 0.95rem;
  text-decoration: none;
  letter-spacing: 0.1em;
}

#back-to-top:hover { color: var(--gold-bright); }

/* ---- RWD ---- */
@media (max-width: 480px) {
  .form-section { padding: 32px 16px 48px; }
  .form-heading { font-size: 1.5rem; }
}