:root {
  --bg: #f5f5f7;
  --surface: rgba(255, 255, 255, 0.72);
  --surface-solid: #ffffff;
  --border: rgba(0, 0, 0, 0.08);
  --border-strong: rgba(0, 0, 0, 0.14);
  --text: #1d1d1f;
  --text-secondary: #6e6e73;
  --text-tertiary: #a1a1a6;
  --accent: #007aff;
  --accent-hover: #0066d6;
  --success: #34c759;
  --danger: #ff3b30;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04), 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.06), 0 1px 3px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.08), 0 8px 20px rgba(0, 0, 0, 0.04);
  --radius-sm: 10px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #000000;
    --surface: rgba(28, 28, 30, 0.72);
    --surface-solid: #1c1c1e;
    --border: rgba(255, 255, 255, 0.08);
    --border-strong: rgba(255, 255, 255, 0.16);
    --text: #f5f5f7;
    --text-secondary: #98989d;
    --text-tertiary: #6e6e73;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3), 0 1px 3px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4), 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.5), 0 8px 20px rgba(0, 0, 0, 0.3);
  }
}

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

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", system-ui, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: "ss01", "cv01", "cv11";
  letter-spacing: -0.01em;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

input {
  font-family: inherit;
}

/* ===== GATE ===== */
.gate {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  padding: 24px;
  z-index: 1000;
  animation: fadeIn 0.4s var(--ease-out);
}

.gate-card {
  width: 100%;
  max-width: 360px;
  background: var(--surface-solid);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 40px 32px 32px;
  text-align: center;
  box-shadow: var(--shadow-lg);
  animation: scaleIn 0.5s var(--ease-spring);
}

.gate-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 72px;
  height: 72px;
  margin-bottom: 20px;
  background: linear-gradient(135deg, #007aff 0%, #0051d5 100%);
  color: white;
  border-radius: 22px;
  box-shadow: 0 8px 20px rgba(0, 122, 255, 0.3);
}

.gate-title {
  font-size: 26px;
  font-weight: 700;
  margin-bottom: 6px;
  letter-spacing: -0.03em;
}

.gate-sub {
  color: var(--text-secondary);
  font-size: 15px;
  margin-bottom: 28px;
}

.gate-form {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.gate-form input {
  width: 100%;
  padding: 14px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  background: var(--bg);
  color: var(--text);
  font-size: 16px;
  outline: none;
  transition: all 0.2s var(--ease-out);
}

.gate-form input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 4px rgba(0, 122, 255, 0.12);
}

.gate-form button {
  width: 100%;
  padding: 14px;
  background: var(--accent);
  color: white;
  font-size: 16px;
  font-weight: 600;
  border-radius: var(--radius-sm);
  transition: all 0.2s var(--ease-out);
}

.gate-form button:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
}

.gate-form button:active {
  transform: scale(0.98);
}

.gate-error {
  color: var(--danger);
  font-size: 14px;
  margin-top: 12px;
  min-height: 20px;
}

/* ===== APP ===== */
.app {
  max-width: 680px;
  margin: 0 auto;
  padding: 32px 24px 80px;
  animation: fadeIn 0.5s var(--ease-out);
}

.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 32px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 19px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.brand-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: linear-gradient(135deg, #007aff, #0051d5);
  box-shadow: 0 0 12px rgba(0, 122, 255, 0.5);
}

.logout-btn {
  width: 38px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  color: var(--text-secondary);
  transition: all 0.2s var(--ease-out);
}

.logout-btn:hover {
  background: var(--border);
  color: var(--text);
}

/* ===== CARDS ===== */
.card {
  background: var(--surface-solid);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  overflow: hidden;
}

.upload-card {
  margin-bottom: 32px;
}

/* ===== DROPZONE ===== */
.dropzone {
  position: relative;
  min-height: 280px;
  padding: 48px 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  transition: background 0.25s var(--ease-out);
}

.dropzone.dragover {
  background: rgba(0, 122, 255, 0.06);
}

.dropzone.dragover .dz-icon {
  color: var(--accent);
  transform: scale(1.1) translateY(-4px);
}

.dz-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  animation: slideUp 0.4s var(--ease-out);
}

.dz-icon {
  color: var(--text-tertiary);
  margin-bottom: 4px;
  transition: all 0.3s var(--ease-spring);
}

.dz-title {
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.dz-sub {
  color: var(--text-secondary);
  font-size: 15px;
}

.dz-browse {
  color: var(--accent);
  font-weight: 500;
  text-decoration: none;
  font-size: inherit;
  padding: 0;
}

.dz-browse:hover {
  text-decoration: underline;
}

.dz-hint {
  color: var(--text-tertiary);
  font-size: 13px;
  margin-top: 6px;
}

/* ===== PROGRESS ===== */
.dz-progress {
  width: 100%;
  max-width: 420px;
  animation: slideUp 0.3s var(--ease-out);
}

.prog-file {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 18px;
  text-align: left;
}

.prog-file-icon {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  border-radius: 12px;
  color: var(--accent);
  flex-shrink: 0;
}

.prog-file-info {
  flex: 1;
  min-width: 0;
}

.prog-file-name {
  font-size: 15px;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.prog-file-meta {
  font-size: 13px;
  color: var(--text-secondary);
  margin-top: 2px;
}

.prog-bar {
  width: 100%;
  height: 6px;
  background: var(--border);
  border-radius: 100px;
  overflow: hidden;
}

.prog-bar-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, #007aff, #0051d5);
  border-radius: 100px;
  transition: width 0.3s var(--ease-out);
}

.prog-status {
  font-size: 13px;
  color: var(--text-secondary);
  margin-top: 12px;
}

/* ===== SUCCESS ===== */
.dz-success {
  width: 100%;
  max-width: 460px;
  animation: slideUp 0.4s var(--ease-spring);
}

.success-check {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 72px;
  height: 72px;
  background: var(--success);
  color: white;
  border-radius: 50%;
  margin-bottom: 16px;
  animation: checkPop 0.5s var(--ease-spring);
  box-shadow: 0 8px 20px rgba(52, 199, 89, 0.3);
}

.success-title {
  font-size: 22px;
  font-weight: 600;
  margin-bottom: 4px;
  letter-spacing: -0.02em;
}

.success-file {
  color: var(--text-secondary);
  font-size: 14px;
  margin-bottom: 20px;
  word-break: break-all;
}

.link-box {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
  padding: 4px;
  background: var(--bg);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

.link-box input {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  color: var(--text);
  font-size: 13px;
  padding: 8px 10px;
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
}

.copy-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  background: var(--accent);
  color: white;
  font-size: 13px;
  font-weight: 500;
  border-radius: 8px;
  transition: all 0.2s var(--ease-out);
}

.copy-btn:hover {
  background: var(--accent-hover);
}

.copy-btn:active {
  transform: scale(0.96);
}

.copy-btn.copied {
  background: var(--success);
}

.new-upload-btn {
  padding: 10px 22px;
  background: var(--bg);
  border: 1px solid var(--border-strong);
  color: var(--text);
  font-size: 14px;
  font-weight: 500;
  border-radius: 100px;
  transition: all 0.2s var(--ease-out);
}

.new-upload-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-1px);
}

/* ===== HISTORY ===== */
.history-section {
  margin-top: 8px;
}

.history-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 4px;
  margin-bottom: 12px;
}

.history-head h2 {
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--text-secondary);
  text-transform: uppercase;
  font-size: 12px;
  letter-spacing: 0.06em;
}

.refresh-btn {
  width: 30px;
  height: 30px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  color: var(--text-secondary);
  transition: all 0.2s var(--ease-out);
}

.refresh-btn:hover {
  background: var(--border);
  color: var(--text);
}

.refresh-btn.spinning svg {
  animation: spin 0.8s linear;
}

.history-list {
  background: var(--surface-solid);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.history-empty {
  padding: 48px 24px;
  text-align: center;
  color: var(--text-tertiary);
  font-size: 14px;
}

.history-item {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 18px;
  border-bottom: 1px solid var(--border);
  transition: background 0.15s;
  animation: slideUp 0.3s var(--ease-out);
}

.history-item:last-child {
  border-bottom: none;
}

.history-item:hover {
  background: var(--bg);
}

.hi-icon {
  width: 38px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  border-radius: 10px;
  color: var(--accent);
  flex-shrink: 0;
}

.hi-info {
  flex: 1;
  min-width: 0;
}

.hi-name {
  font-size: 14.5px;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.hi-meta {
  font-size: 12.5px;
  color: var(--text-secondary);
  margin-top: 2px;
  display: flex;
  gap: 8px;
}

.hi-actions {
  display: flex;
  gap: 4px;
  flex-shrink: 0;
}

.hi-btn {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  color: var(--text-secondary);
  transition: all 0.2s var(--ease-out);
}

.hi-btn:hover {
  background: var(--border);
  color: var(--text);
}

.hi-btn.copied {
  color: var(--success);
}

.hi-btn.delete:hover {
  color: var(--danger);
  background: rgba(255, 59, 48, 0.1);
}

/* ===== FOOTER ===== */
.footer {
  margin-top: 40px;
  text-align: center;
  color: var(--text-tertiary);
  font-size: 12px;
}

/* ===== TOAST ===== */
.toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--text);
  color: var(--bg);
  padding: 12px 20px;
  border-radius: 100px;
  font-size: 14px;
  font-weight: 500;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  pointer-events: none;
  transition: all 0.3s var(--ease-spring);
  z-index: 9999;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ===== ANIMATIONS ===== */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

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

@keyframes scaleIn {
  from { opacity: 0; transform: scale(0.94); }
  to { opacity: 1; transform: scale(1); }
}

@keyframes checkPop {
  0% { transform: scale(0); opacity: 0; }
  60% { transform: scale(1.15); opacity: 1; }
  100% { transform: scale(1); }
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ===== RESPONSIVE ===== */
@media (max-width: 520px) {
  .app {
    padding: 20px 16px 60px;
  }
  .dropzone {
    min-height: 240px;
    padding: 36px 18px;
  }
  .dz-title {
    font-size: 20px;
  }
  .link-box {
    flex-direction: column;
  }
  .copy-btn {
    justify-content: center;
  }
}