/* ═══════════════════════════════════════════════════════════════════
   KamiDrop – Cupertino Design System
   ═══════════════════════════════════════════════════════════════════ */

/* ── CSS Custom Properties ─────────────────────────────────────── */
:root {
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Segoe UI', Roboto, sans-serif;

  /* Light Mode */
  --bg: #f5f5f7;
  --bg-elevated: #ffffff;
  --bg-glass: rgba(255,255,255,0.72);
  --bg-glass-heavy: rgba(255,255,255,0.88);
  --border: rgba(0,0,0,0.08);
  --border-strong: rgba(0,0,0,0.14);

  --text-primary: #1d1d1f;
  --text-secondary: #6e6e73;
  --text-tertiary: #aeaeb2;

  --accent: #007AFF;
  --accent-hover: #0066d6;
  --accent-light: rgba(0,122,255,0.1);
  --accent-gradient: linear-gradient(135deg, #007AFF 0%, #5856D6 100%);

  --success: #34C759;
  --warning: #FF9500;
  --danger: #FF3B30;

  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 14px rgba(0,0,0,0.08), 0 2px 6px rgba(0,0,0,0.04);
  --shadow-lg: 0 12px 40px rgba(0,0,0,0.12), 0 4px 12px rgba(0,0,0,0.06);
  --shadow-accent: 0 4px 14px rgba(0,122,255,0.3);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-full: 999px;

  --transition: 0.2s cubic-bezier(0.25, 0.1, 0.25, 1);
  --transition-spring: 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

[data-theme="dark"] {
  --bg: #000000;
  --bg-elevated: #1c1c1e;
  --bg-glass: rgba(44,44,46,0.72);
  --bg-glass-heavy: rgba(44,44,46,0.88);
  --border: rgba(255,255,255,0.08);
  --border-strong: rgba(255,255,255,0.16);
  --text-primary: #f5f5f7;
  --text-secondary: #98989d;
  --text-tertiary: #636366;
  --accent: #0A84FF;
  --accent-hover: #409cff;
  --accent-light: rgba(10,132,255,0.15);
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 14px rgba(0,0,0,0.4);
  --shadow-lg: 0 12px 40px rgba(0,0,0,0.5);
  --shadow-accent: 0 4px 14px rgba(10,132,255,0.35);
}

/* ── Reset & Base ──────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text-primary);
  line-height: 1.5;
  min-height: 100vh;
  transition: background var(--transition), color var(--transition);
  overflow-x: hidden;
}

/* ── Header ────────────────────────────────────────────────────── */
.app-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: var(--bg-glass-heavy);
  backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  transition: background var(--transition);
}
.header-inner {
  max-width: 960px; margin: 0 auto;
  padding: 0 24px; height: 56px;
  display: flex; align-items: center; justify-content: space-between;
}
.header-brand {
  display: flex; align-items: center; gap: 10px;
  cursor: pointer; user-select: none;
}
.brand-icon { width: 28px; height: 28px; }
.brand-text {
  font-size: 1.125rem; font-weight: 700;
  background: var(--accent-gradient); -webkit-background-clip: text;
  -webkit-text-fill-color: transparent; background-clip: text;
}

/* ── Theme Toggle ──────────────────────────────────────────────── */
.icon-moon { display: none; }
[data-theme="dark"] .icon-sun { display: none; }
[data-theme="dark"] .icon-moon { display: block; }

/* ── App Grid (Google-style) ──────────────────────────────────── */
.header-actions {
  display: flex; align-items: center; gap: 4px;
}
.app-grid-trigger {
  position: relative;
}
.app-grid-menu {
  position: absolute; top: 48px; right: 0;
  width: 280px; padding: 16px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  opacity: 0; visibility: hidden;
  transform: scale(0.95) translateY(-8px);
  transition: all var(--transition);
  z-index: 200;
}
.app-grid-menu.open {
  opacity: 1; visibility: visible;
  transform: scale(1) translateY(0);
}
.app-grid-title {
  font-size: 0.6875rem; font-weight: 600; text-transform: uppercase;
  letter-spacing: 0.06em; color: var(--text-tertiary);
  margin-bottom: 12px; padding: 0 4px;
}
.app-grid-list {
  display: grid; grid-template-columns: 1fr 1fr; gap: 4px;
  list-style: none;
}
.app-grid-item {
  display: flex; flex-direction: column; align-items: center; gap: 8px;
  padding: 16px 8px; border-radius: var(--radius-md);
  text-decoration: none; color: var(--text-primary);
  transition: all var(--transition);
  cursor: pointer;
}
.app-grid-item:hover {
  background: var(--accent-light);
}
.app-grid-item.active {
  background: var(--accent-light);
}
.app-grid-icon {
  width: 40px; height: 40px; border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
}
.app-grid-label {
  font-size: 0.75rem; font-weight: 600; text-align: center;
  line-height: 1.3;
}

/* ── Buttons ───────────────────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 10px 22px; border: none; border-radius: var(--radius-full);
  font-family: var(--font); font-size: 0.9375rem; font-weight: 600;
  cursor: pointer; transition: all var(--transition);
  user-select: none; white-space: nowrap;
}
.btn:active { transform: scale(0.97); }

.btn-primary {
  background: var(--accent); color: #fff;
  box-shadow: var(--shadow-accent);
}
.btn-primary:hover { background: var(--accent-hover); }
.btn-primary:disabled {
  opacity: 0.4; cursor: not-allowed;
  box-shadow: none; transform: none;
}

.btn-secondary {
  background: var(--accent-light); color: var(--accent);
  border: 1px solid transparent;
}
.btn-secondary:hover { background: var(--accent); color: #fff; }

.btn-sm { padding: 7px 14px; font-size: 0.8125rem; }

.btn-icon {
  width: 40px; height: 40px; border: none; border-radius: var(--radius-md);
  background: transparent; color: var(--text-primary);
  display: flex; align-items: center; justify-content: center;
  cursor: pointer; transition: all var(--transition);
}
.btn-icon:hover { background: var(--accent-light); color: var(--accent); }
.btn-icon svg { width: 20px; height: 20px; }

.btn-icon-sm {
  width: 28px; height: 28px; border: none; border-radius: var(--radius-sm);
  background: transparent; color: var(--text-secondary);
  display: flex; align-items: center; justify-content: center;
  cursor: pointer; transition: all var(--transition);
}
.btn-icon-sm:hover { color: var(--accent); }
.btn-icon-sm svg { width: 16px; height: 16px; }

/* ── Inputs ────────────────────────────────────────────────────── */
.input {
  width: 100%; padding: 10px 16px;
  background: var(--bg-elevated); color: var(--text-primary);
  border: 1.5px solid var(--border-strong); border-radius: var(--radius-md);
  font-family: var(--font); font-size: 0.9375rem;
  transition: all var(--transition); outline: none;
}
.input::placeholder { color: var(--text-tertiary); }
.input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-light);
}

/* ── Glass Card ────────────────────────────────────────────────── */
.glass-card {
  background: var(--bg-glass);
  backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

/* ── Views ─────────────────────────────────────────────────────── */
.app-main { padding-top: 56px; min-height: 100vh; }

.view {
  display: none; opacity: 0;
  animation: viewFadeIn 0.35s ease forwards;
}
.view.active { display: block; opacity: 1; }

@keyframes viewFadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ── Home View ─────────────────────────────────────────────────── */
.home-container {
  max-width: 720px; margin: 0 auto;
  padding: 48px 24px 64px;
}

.home-hero {
  text-align: center; margin-bottom: 48px;
}
.hero-icon-wrapper {
  display: inline-block; margin-bottom: 20px;
  animation: heroFloat 6s ease-in-out infinite;
}
.hero-icon { width: 80px; height: 80px; }
@keyframes heroFloat {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-8px); }
}

.hero-title {
  font-size: 2.5rem; font-weight: 800; letter-spacing: -0.03em;
  background: var(--accent-gradient); -webkit-background-clip: text;
  -webkit-text-fill-color: transparent; background-clip: text;
  margin-bottom: 8px;
}
.hero-subtitle {
  font-size: 1.125rem; color: var(--text-secondary);
  max-width: 400px; margin: 0 auto; line-height: 1.6;
}

.home-actions {
  display: grid; grid-template-columns: 1fr 1fr; gap: 20px;
  margin-bottom: 48px;
}

.action-card {
  background: var(--bg-glass);
  backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl); padding: 32px 24px;
  text-align: center;
  box-shadow: var(--shadow-md);
  transition: all var(--transition);
}
.action-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
  border-color: var(--accent);
}

.action-card-icon {
  width: 48px; height: 48px; margin: 0 auto 16px;
  display: flex; align-items: center; justify-content: center;
  background: var(--accent-light); border-radius: var(--radius-md);
  color: var(--accent);
}
.action-card-icon svg { width: 24px; height: 24px; }

.action-card h2 {
  font-size: 1.125rem; font-weight: 700; margin-bottom: 6px;
}
.action-card p {
  font-size: 0.875rem; color: var(--text-secondary);
  margin-bottom: 20px; line-height: 1.5;
}

.join-input-group { display: flex; flex-direction: column; gap: 10px; }
.join-input-group .input {
  text-align: center; font-size: 1rem; letter-spacing: 0.05em;
  font-variant-numeric: tabular-nums;
}

.home-features {
  display: flex; justify-content: center; gap: 32px; flex-wrap: wrap;
}
.feature-item {
  display: flex; align-items: center; gap: 8px;
  font-size: 0.875rem; color: var(--text-secondary);
}
.feature-icon { font-size: 1.125rem; }

/* ── Room View ─────────────────────────────────────────────────── */
.room-container {
  max-width: 720px; margin: 0 auto;
  padding: 24px 24px 64px;
}

.room-header {
  display: flex; align-items: center; gap: 16px;
  padding: 12px 16px; margin-bottom: 20px;
}
.room-header-info { flex: 1; min-width: 0; }

.room-code-label {
  font-size: 0.6875rem; font-weight: 600; text-transform: uppercase;
  letter-spacing: 0.06em; color: var(--text-tertiary);
}
.room-code-value-wrap { display: flex; align-items: center; gap: 6px; }
.room-code-value {
  font-size: 1rem; font-weight: 700; letter-spacing: 0.04em;
  font-variant-numeric: tabular-nums; color: var(--text-primary);
}

.connection-status { display: flex; align-items: center; gap: 6px; margin-top: 2px; }
.status-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--warning);
  animation: statusPulse 2s ease-in-out infinite;
}
.status-dot.connected { background: var(--success); animation: none; }
.status-dot.disconnected { background: var(--danger); animation: none; }
.status-text { font-size: 0.75rem; color: var(--text-secondary); }

@keyframes statusPulse {
  0%, 100% { opacity: 1; }
  50%      { opacity: 0.4; }
}

/* ── Tab Bar ───────────────────────────────────────────────────── */
.tab-bar {
  display: flex; gap: 4px; padding: 4px;
  background: var(--bg-glass); border-radius: var(--radius-full);
  border: 1px solid var(--border);
  margin-bottom: 20px;
}
.tab {
  flex: 1; display: flex; align-items: center; justify-content: center; gap: 6px;
  padding: 10px 16px; border: none; border-radius: var(--radius-full);
  background: transparent; color: var(--text-secondary);
  font-family: var(--font); font-size: 0.875rem; font-weight: 600;
  cursor: pointer; transition: all var(--transition);
}
.tab:hover { color: var(--text-primary); }
.tab.active {
  background: var(--bg-elevated); color: var(--text-primary);
  box-shadow: var(--shadow-sm);
}

.tab-content { display: none; animation: viewFadeIn 0.25s ease forwards; }
.tab-content.active { display: block; }

/* ── Drop Zone ─────────────────────────────────────────────────── */
.drop-zone {
  position: relative; padding: 48px 24px;
  border: 2px dashed var(--border-strong); border-radius: var(--radius-xl);
  background: var(--bg-glass);
  cursor: pointer; transition: all var(--transition);
  text-align: center;
}
.drop-zone:hover, .drop-zone.dragover {
  border-color: var(--accent);
  background: var(--accent-light);
}
.drop-zone.dragover { transform: scale(1.01); }

.drop-zone-icon {
  width: 48px; height: 48px; margin: 0 auto 12px;
  color: var(--text-tertiary);
  transition: color var(--transition);
}
.drop-zone:hover .drop-zone-icon,
.drop-zone.dragover .drop-zone-icon { color: var(--accent); }

.drop-zone-inner h3 { font-size: 1rem; font-weight: 600; margin-bottom: 4px; }
.drop-zone-inner p  { font-size: 0.875rem; color: var(--text-secondary); }
.drop-zone-hint {
  display: inline-block; margin-top: 12px; padding: 4px 10px;
  font-size: 0.75rem; color: var(--warning);
  background: rgba(255,149,0,0.1); border-radius: var(--radius-full);
}

/* ── Transfer List ─────────────────────────────────────────────── */
.transfer-list { display: flex; flex-direction: column; gap: 10px; margin-top: 16px; }

.transfer-item {
  display: flex; align-items: center; gap: 14px;
  padding: 14px 16px;
  background: var(--bg-glass);
  backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--border); border-radius: var(--radius-lg);
  transition: all var(--transition);
}

.transfer-icon {
  width: 40px; height: 40px; flex-shrink: 0;
  display: flex; align-items: center; justify-content: center;
  border-radius: var(--radius-md);
  font-size: 1.25rem;
}
.transfer-icon.sending   { background: rgba(0,122,255,0.1); color: var(--accent); }
.transfer-icon.receiving { background: rgba(52,199,89,0.1);  color: var(--success); }
.transfer-icon.complete  { background: rgba(52,199,89,0.1);  color: var(--success); }
.transfer-icon.error     { background: rgba(255,59,48,0.1);  color: var(--danger); }

.transfer-info { flex: 1; min-width: 0; }
.transfer-name {
  font-size: 0.875rem; font-weight: 600;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.transfer-meta {
  font-size: 0.75rem; color: var(--text-secondary); margin-top: 2px;
}

.transfer-progress {
  width: 100%; height: 4px; margin-top: 8px;
  background: var(--border); border-radius: 2px; overflow: hidden;
}
.transfer-progress-bar {
  height: 100%; width: 0%;
  background: var(--accent-gradient); border-radius: 2px;
  transition: width 0.3s ease;
}
.transfer-progress-bar.complete { background: var(--success); }

.transfer-actions { display: flex; gap: 4px; }

.btn-download {
  padding: 6px 14px; border: none; border-radius: var(--radius-full);
  background: var(--success); color: #fff;
  font-family: var(--font); font-size: 0.8125rem; font-weight: 600;
  cursor: pointer; transition: all var(--transition);
}
.btn-download:hover { filter: brightness(1.1); }

/* ── Text Tab ──────────────────────────────────────────────────── */
.text-composer {
  padding: 16px; margin-bottom: 16px;
  display: flex; flex-direction: column; gap: 12px;
}
.text-input {
  resize: vertical; min-height: 80px; max-height: 240px;
  border: none; background: transparent; padding: 0;
  font-size: 0.9375rem;
}
.text-input:focus { box-shadow: none; }
.text-composer .btn-primary { align-self: flex-end; }

.text-messages { display: flex; flex-direction: column; gap: 10px; }

.text-message {
  padding: 14px 16px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  animation: viewFadeIn 0.25s ease forwards;
}
.text-message.sent {
  background: var(--accent); color: #fff;
  border-color: transparent; align-self: flex-end;
  max-width: 85%;
}
.text-message.received {
  background: var(--bg-glass);
  backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
  max-width: 85%;
}

.text-message-header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 6px;
}
.text-message-label {
  font-size: 0.6875rem; font-weight: 600; text-transform: uppercase;
  letter-spacing: 0.04em; opacity: 0.7;
}
.text-message-body {
  font-size: 0.9375rem; line-height: 1.6;
  white-space: pre-wrap; word-break: break-word;
}
.btn-copy-text {
  padding: 4px 10px; border: none; border-radius: var(--radius-full);
  font-family: var(--font); font-size: 0.6875rem; font-weight: 600;
  cursor: pointer; transition: all var(--transition);
}
.text-message.received .btn-copy-text {
  background: var(--accent-light); color: var(--accent);
}
.text-message.received .btn-copy-text:hover {
  background: var(--accent); color: #fff;
}

/* ── Toast ──────────────────────────────────────────────────────── */
.toast-container {
  position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%);
  z-index: 1000; display: flex; flex-direction: column-reverse; gap: 8px;
  pointer-events: none;
}
.toast {
  padding: 12px 20px; border-radius: var(--radius-full);
  background: var(--bg-elevated); color: var(--text-primary);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-lg);
  font-size: 0.875rem; font-weight: 500;
  white-space: nowrap; pointer-events: auto;
  animation: toastIn 0.35s var(--transition-spring) forwards;
}
.toast.toast-out { animation: toastOut 0.25s ease forwards; }
.toast.success { border-color: var(--success); color: var(--success); }
.toast.error   { border-color: var(--danger);  color: var(--danger); }

@keyframes toastIn {
  from { opacity: 0; transform: translateY(16px) scale(0.95); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}
@keyframes toastOut {
  from { opacity: 1; transform: translateY(0) scale(1); }
  to   { opacity: 0; transform: translateY(8px) scale(0.95); }
}

/* ── Responsive ────────────────────────────────────────────────── */
@media (max-width: 600px) {
  .home-actions { grid-template-columns: 1fr; }
  .hero-title { font-size: 2rem; }
  .home-features { flex-direction: column; align-items: center; gap: 16px; }
  .room-header { flex-wrap: wrap; }
  .room-header .btn { width: 100%; }
  .app-grid-menu { right: -60px; }
}