:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-card: #1a1a25;
  --bg-hover: #22222f;
  --border: #2a2a3a;
  --border-focus: #6c5ce7;
  --text-primary: #e8e8f0;
  --text-secondary: #8888a0;
  --text-muted: #55556a;
  --accent: #6c5ce7;
  --accent-hover: #7e70f0;
  --accent-glow: rgba(108, 92, 231, 0.25);
  --success: #00d2a0;
  --success-bg: rgba(0, 210, 160, 0.1);
  --danger: #ff4757;
  --danger-bg: rgba(255, 71, 87, 0.1);
  --warning: #ffa502;
  --warning-bg: rgba(255, 165, 2, 0.1);
  --radius: 12px;
  --radius-sm: 8px;
  --radius-lg: 16px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 48px rgba(0, 0, 0, 0.5);
  --transition: 0.2s ease;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--accent-hover);
}

/* ── Layout ────────────────────────────────────────── */

.app {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.container {
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ── Header ────────────────────────────────────────── */

.header {
  border-bottom: 1px solid var(--border);
  background: var(--bg-secondary);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
}

.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.logo-icon {
  width: 32px;
  height: 32px;
  background: var(--accent);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
}

.nav {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-link {
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  transition: all var(--transition);
}

.nav-link:hover {
  color: var(--text-primary);
  background: var(--bg-hover);
}

.nav-link.active {
  color: var(--accent);
  background: var(--accent-glow);
}

/* ── Hero ──────────────────────────────────────────── */

.hero {
  padding: 80px 0 60px;
  text-align: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  background: var(--accent-glow);
  border: 1px solid rgba(108, 92, 231, 0.3);
  border-radius: 24px;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 24px;
}

.hero h1 {
  font-size: 3rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 16px;
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 520px;
  margin: 0 auto 36px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ── Buttons ───────────────────────────────────────── */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: var(--radius);
  font-size: 0.9375rem;
  font-weight: 600;
  font-family: var(--font);
  cursor: pointer;
  border: none;
  transition: all var(--transition);
  white-space: nowrap;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 2px 12px var(--accent-glow);
}

.btn-primary:hover:not(:disabled) {
  background: var(--accent-hover);
  box-shadow: 0 4px 20px var(--accent-glow);
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--bg-hover);
  border-color: var(--text-muted);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  padding: 8px 16px;
}

.btn-ghost:hover {
  color: var(--text-primary);
  background: var(--bg-hover);
}

.btn-sm {
  padding: 8px 18px;
  font-size: 0.8125rem;
}

.btn-icon {
  width: 40px;
  height: 40px;
  padding: 0;
  border-radius: var(--radius-sm);
}

/* ── Cards ─────────────────────────────────────────── */

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow);
}

.card-header {
  margin-bottom: 24px;
}

.card-header h2 {
  font-size: 1.375rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 6px;
}

.card-header p {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

/* ── Features ──────────────────────────────────────── */

.features {
  padding: 60px 0;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  transition: all var(--transition);
}

.feature-card:hover {
  border-color: var(--accent);
  box-shadow: 0 0 24px var(--accent-glow);
  transform: translateY(-2px);
}

.feature-icon {
  width: 48px;
  height: 48px;
  background: var(--accent-glow);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  margin-bottom: 16px;
}

.feature-card h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 0.8125rem;
  line-height: 1.6;
}

/* ── Upload Page ───────────────────────────────────── */

.upload-section {
  padding: 48px 0;
}

.upload-card {
  max-width: 640px;
  margin: 0 auto;
}

.dropzone {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 56px 32px;
  text-align: center;
  cursor: pointer;
  transition: all var(--transition);
  background: var(--bg-secondary);
  position: relative;
}

.dropzone:hover {
  border-color: var(--accent);
  background: rgba(108, 92, 231, 0.04);
}

.dropzone.dragover {
  border-color: var(--accent);
  background: var(--accent-glow);
  box-shadow: 0 0 32px var(--accent-glow);
}

.dropzone-icon {
  font-size: 2.5rem;
  margin-bottom: 16px;
  opacity: 0.6;
}

.dropzone h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.dropzone p {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.dropzone .browse-link {
  color: var(--accent);
  font-weight: 600;
  cursor: pointer;
}

.dropzone .browse-link:hover {
  text-decoration: underline;
}

.dropzone input[type="file"] {
  display: none;
}

/* File selected state */
.file-selected {
  display: none;
  align-items: center;
  gap: 16px;
  padding: 16px 20px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  margin-top: 20px;
}

.file-selected.active {
  display: flex;
}

.file-icon {
  width: 44px;
  height: 44px;
  background: var(--accent-glow);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.125rem;
  flex-shrink: 0;
}

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

.file-name {
  font-weight: 600;
  font-size: 0.875rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.file-size {
  color: var(--text-secondary);
  font-size: 0.8125rem;
}

.file-remove {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 4px;
  font-size: 1.125rem;
  transition: color var(--transition);
}

.file-remove:hover {
  color: var(--danger);
}

/* Options row */
.upload-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 20px;
}

.form-group label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.form-select {
  width: 100%;
  padding: 10px 14px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font);
  font-size: 0.875rem;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%238888a0' viewBox='0 0 16 16'%3E%3Cpath d='M8 11L3 6h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  cursor: pointer;
  transition: border-color var(--transition);
}

.form-select:focus {
  outline: none;
  border-color: var(--border-focus);
}

.upload-actions {
  margin-top: 24px;
}

.upload-actions .btn {
  width: 100%;
  padding: 14px;
}

/* Progress */
.progress-container {
  display: none;
  margin-top: 24px;
}

.progress-container.active {
  display: block;
}

.progress-bar-track {
  height: 6px;
  background: var(--bg-secondary);
  border-radius: 3px;
  overflow: hidden;
  margin-bottom: 12px;
}

.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--success));
  border-radius: 3px;
  width: 0%;
  transition: width 0.3s ease;
}

.progress-status {
  display: flex;
  justify-content: space-between;
  font-size: 0.8125rem;
  color: var(--text-secondary);
}

.progress-status .status-text {
  color: var(--accent);
  font-weight: 500;
}

/* ── Result ────────────────────────────────────────── */

.result {
  display: none;
  margin-top: 24px;
}

.result.active {
  display: block;
}

.result-success {
  padding: 24px;
  background: var(--success-bg);
  border: 1px solid rgba(0, 210, 160, 0.2);
  border-radius: var(--radius);
}

.result-success h3 {
  color: var(--success);
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.result-success p {
  color: var(--text-secondary);
  font-size: 0.8125rem;
  margin-bottom: 16px;
}

.result-url {
  display: flex;
  gap: 8px;
}

.result-url input {
  flex: 1;
  padding: 10px 14px;
  background: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
}

.result-url input:focus {
  outline: none;
  border-color: var(--accent);
}

.result-url .btn {
  flex-shrink: 0;
}

.copied-toast {
  display: none;
  padding: 8px 16px;
  background: var(--success);
  color: #fff;
  border-radius: var(--radius-sm);
  font-size: 0.8125rem;
  font-weight: 600;
  margin-top: 12px;
  text-align: center;
}

.copied-toast.active {
  display: block;
  animation: fadeIn 0.2s ease;
}

/* ── Download Page ─────────────────────────────────── */

.download-section {
  padding: 48px 0;
}

.download-card {
  max-width: 520px;
  margin: 0 auto;
  text-align: center;
}

.download-card .file-icon {
  width: 64px;
  height: 64px;
  font-size: 1.75rem;
  margin: 0 auto 20px;
}

.download-meta {
  margin-bottom: 28px;
}

.download-meta h2 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 8px;
  word-break: break-all;
}

.download-meta-list {
  display: flex;
  justify-content: center;
  gap: 24px;
  color: var(--text-secondary);
  font-size: 0.8125rem;
}

.download-meta-list span {
  display: flex;
  align-items: center;
  gap: 6px;
}

.download-card .btn {
  width: 100%;
  padding: 14px;
}

.key-input-group {
  display: none;
  margin-bottom: 24px;
}

.key-input-group.active {
  display: block;
}

.key-input-group label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.key-input-group input {
  width: 100%;
  padding: 12px 14px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 0.875rem;
}

.key-input-group input:focus {
  outline: none;
  border-color: var(--border-focus);
}

/* Error states */
.error-message {
  display: none;
  padding: 16px 20px;
  background: var(--danger-bg);
  border: 1px solid rgba(255, 71, 87, 0.2);
  border-radius: var(--radius);
  color: var(--danger);
  font-size: 0.875rem;
  margin-top: 20px;
}

.error-message.active {
  display: block;
}

.expired-message {
  display: none;
  padding: 24px;
  background: var(--warning-bg);
  border: 1px solid rgba(255, 165, 2, 0.2);
  border-radius: var(--radius);
  text-align: center;
}

.expired-message.active {
  display: block;
}

.expired-message h3 {
  color: var(--warning);
  font-size: 1.125rem;
  margin-bottom: 8px;
}

.expired-message p {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

/* ── Footer ────────────────────────────────────────── */

.footer {
  margin-top: auto;
  border-top: 1px solid var(--border);
  padding: 24px 0;
}

.footer .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8125rem;
  color: var(--text-muted);
}

.footer-links {
  display: flex;
  gap: 16px;
}

.footer-links a {
  color: var(--text-muted);
}

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

/* ── E2EE Info Banner ──────────────────────────────── */

.e2ee-banner {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 20px;
  background: var(--accent-glow);
  border: 1px solid rgba(108, 92, 231, 0.2);
  border-radius: var(--radius);
  margin-bottom: 24px;
  font-size: 0.8125rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

.e2ee-banner .icon {
  font-size: 1.25rem;
  flex-shrink: 0;
}

.e2ee-banner strong {
  color: var(--text-primary);
}

/* ── Animations ────────────────────────────────────── */

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

.fade-in {
  animation: fadeIn 0.3s ease;
}

/* ── Responsive ────────────────────────────────────── */

@media (max-width: 768px) {
  .hero h1 {
    font-size: 2rem;
  }

  .features-grid {
    grid-template-columns: 1fr;
  }

  .upload-options {
    grid-template-columns: 1fr;
  }

  .header .container {
    padding: 0 16px;
  }

  .container {
    padding: 0 16px;
  }

  .card {
    padding: 24px;
  }

  .hero {
    padding: 48px 0 36px;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 1.625rem;
  }

  .hero p {
    font-size: 1rem;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .result-url {
    flex-direction: column;
  }

  .download-meta-list {
    flex-direction: column;
    gap: 8px;
  }
}