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

:root {
  --bg: #0a0e1a;
  --surface: #131830;
  --card: #1a2040;
  --primary: #6366f1;
  --primary-glow: #818cf850;
  --text: #e2e8f0;
  --text-dim: #94a3b8;
  --border: #2a3060;
  --radius: 16px;
}

body {
  font-family: 'Inter', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

.page {
  display: none;
}

.page.active {
  display: block;
}

/* Navbar */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: #0a0e1aee;
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
}

.logo-icon {
  font-size: 28px;
}

.logo-text {
  font-size: 20px;
  font-weight: 700;
  background: linear-gradient(135deg, #6366f1, #a78bfa);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.nav-badge {
  font-size: 12px;
  color: var(--text-dim);
  background: var(--card);
  padding: 6px 14px;
  border-radius: 20px;
  border: 1px solid var(--border);
}

/* Hero */
.hero {
  position: relative;
  text-align: center;
  padding: 80px 24px 60px;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 50% 0%, #6366f130 0%, transparent 60%);
}

.hero-content {
  position: relative;
}

.hero h1 {
  font-size: 42px;
  font-weight: 800;
  margin-bottom: 16px;
  background: linear-gradient(135deg, #fff, #a78bfa);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 16px;
  color: var(--text-dim);
  margin-bottom: 32px;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 48px;
}

.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.stat-num {
  font-size: 28px;
  font-weight: 800;
  color: #a78bfa;
}

.stat-label {
  font-size: 13px;
  color: var(--text-dim);
  margin-top: 4px;
}

/* Tools Section */
.tools-section {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px 60px;
}

.category {
  margin-bottom: 48px;
}

.category-title {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.cat-icon {
  font-size: 24px;
}

.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 16px;
}

/* Tool Card */
.tool-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 20px;
  cursor: pointer;
  transition: all 0.3s ease;
  text-align: center;
}

.tool-card:hover {
  transform: translateY(-4px);
  border-color: var(--primary);
  box-shadow: 0 8px 32px var(--primary-glow);
  background: linear-gradient(135deg, var(--card), #1e2550);
}

.card-icon {
  font-size: 36px;
  margin-bottom: 12px;
}

.tool-card h3 {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 6px;
}

.tool-card p {
  font-size: 12px;
  color: var(--text-dim);
  line-height: 1.5;
}

/* Tool Page */
.tool-header {
  text-align: center;
  padding: 40px 24px 20px;
}

.back-btn {
  background: var(--card);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 10px 20px;
  border-radius: 10px;
  cursor: pointer;
  font-size: 14px;
  margin-bottom: 20px;
  transition: all 0.2s;
}

.back-btn:hover {
  border-color: var(--primary);
  background: var(--surface);
}

.tool-title {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 8px;
}

.tool-desc {
  color: var(--text-dim);
  font-size: 14px;
}

.tool-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 20px 24px 60px;
}

/* Upload Area */
.upload-area {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 48px;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s;
  margin-bottom: 24px;
}

.upload-area:hover,
.upload-area.dragover {
  border-color: var(--primary);
  background: #6366f10a;
}

.upload-area .icon {
  font-size: 48px;
  margin-bottom: 12px;
}

.upload-area p {
  color: var(--text-dim);
  font-size: 14px;
}

.upload-area input[type="file"] {
  display: none;
}

/* Forms */
.form-group {
  margin-bottom: 16px;
}

.form-group label {
  display: block;
  font-size: 13px;
  color: var(--text-dim);
  margin-bottom: 6px;
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 10px 14px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text);
  font-size: 14px;
  outline: none;
}

.form-group input:focus,
.form-group select:focus {
  border-color: var(--primary);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 12px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all 0.2s;
}

.btn-primary {
  background: linear-gradient(135deg, #6366f1, #8b5cf6);
  color: #fff;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 20px #6366f140;
}

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

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

.btn-download {
  background: linear-gradient(135deg, #10b981, #059669);
  color: #fff;
}

.btn-download:hover {
  box-shadow: 0 4px 20px #10b98140;
}

/* File Info */
.file-info {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.file-info .fi-icon {
  font-size: 32px;
}

.file-info .fi-name {
  font-weight: 600;
  font-size: 14px;
}

.file-info .fi-size {
  font-size: 12px;
  color: var(--text-dim);
}

/* Preview Grid */
.preview-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: 12px;
  margin-bottom: 24px;
}

.preview-item {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 8px;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s;
  position: relative;
}

.preview-item.selected {
  border-color: var(--primary);
  box-shadow: 0 0 12px var(--primary-glow);
}

.preview-item canvas {
  width: 100%;
  border-radius: 6px;
}

.preview-item .page-num {
  font-size: 11px;
  color: var(--text-dim);
  margin-top: 4px;
}

/* Progress */
.progress-bar {
  width: 100%;
  height: 6px;
  background: var(--card);
  border-radius: 3px;
  overflow: hidden;
  margin: 16px 0;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, #6366f1, #a78bfa);
  border-radius: 3px;
  transition: width 0.3s;
  width: 0%;
}

/* Result */
.result-box {
  background: #10b98115;
  border: 1px solid #10b98140;
  border-radius: 12px;
  padding: 24px;
  text-align: center;
  margin-top: 20px;
}

.result-box .icon {
  font-size: 36px;
  margin-bottom: 8px;
}

.result-box p {
  color: #10b981;
  font-size: 14px;
  margin-bottom: 16px;
}

/* Signature Canvas */
.sign-canvas-wrap {
  border: 2px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  margin-bottom: 16px;
  background: #fff;
}

.sign-canvas-wrap canvas {
  width: 100%;
  display: block;
}

/* Watermark Options */
.wm-options {
  display: flex;
  gap: 12px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.wm-options .opt {
  padding: 8px 16px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  font-size: 13px;
  color: var(--text-dim);
  transition: all 0.2s;
}

.wm-options .opt.active {
  border-color: var(--primary);
  color: var(--text);
  background: #6366f115;
}

/* Multi-file list */
.file-list {
  margin-bottom: 20px;
}

.file-list-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  margin-bottom: 8px;
}

.file-list-item .fli-name {
  flex: 1;
  font-size: 13px;
}

.file-list-item .fli-remove {
  cursor: pointer;
  color: #ef4444;
  font-size: 18px;
}

.file-list-item .fli-handle {
  cursor: grab;
  color: var(--text-dim);
}

/* Footer */
.footer {
  text-align: center;
  padding: 32px;
  color: var(--text-dim);
  font-size: 13px;
  border-top: 1px solid var(--border);
}

/* Responsive - Tablet */
@media (max-width: 768px) {
  .hero {
    padding: 50px 16px 40px;
  }

  .hero h1 {
    font-size: 30px;
  }

  .hero-subtitle {
    font-size: 14px;
  }

  .hero-stats {
    gap: 32px;
  }

  .stat-num {
    font-size: 24px;
  }

  .tools-section {
    padding: 0 16px 40px;
  }

  .tools-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
  }

  .tool-card {
    padding: 20px 14px;
  }

  .card-icon {
    font-size: 28px;
    margin-bottom: 8px;
  }

  .tool-card h3 {
    font-size: 14px;
  }

  .tool-title {
    font-size: 24px;
  }

  .tool-content {
    padding: 16px 16px 40px;
  }

  .upload-area {
    padding: 32px 16px;
  }

  .preview-grid {
    grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
    gap: 8px;
  }
}

/* Responsive - Mobile */
@media (max-width: 480px) {
  .nav-container {
    padding: 12px 16px;
  }

  .nav-badge {
    display: none;
  }

  .logo-text {
    font-size: 17px;
  }

  .logo-icon {
    font-size: 24px;
  }

  .hero {
    padding: 36px 16px 28px;
  }

  .hero h1 {
    font-size: 24px;
    margin-bottom: 10px;
  }

  .hero-subtitle {
    font-size: 13px;
    margin-bottom: 20px;
  }

  .hero-stats {
    gap: 20px;
  }

  .stat-num {
    font-size: 20px;
  }

  .stat-label {
    font-size: 11px;
  }

  .tools-section {
    padding: 0 12px 32px;
  }

  .category {
    margin-bottom: 32px;
  }

  .category-title {
    font-size: 17px;
    margin-bottom: 14px;
  }

  .tools-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
  }

  .tool-card {
    padding: 18px 12px;
    border-radius: 12px;
  }

  .card-icon {
    font-size: 26px;
  }

  .tool-card h3 {
    font-size: 13px;
  }

  .tool-card p {
    font-size: 11px;
  }

  .tool-header {
    padding: 24px 16px 12px;
  }

  .back-btn {
    padding: 8px 16px;
    font-size: 13px;
  }

  .tool-title {
    font-size: 20px;
  }

  .tool-desc {
    font-size: 13px;
  }

  .tool-content {
    padding: 12px 12px 32px;
  }

  .upload-area {
    padding: 28px 12px;
    border-radius: 12px;
  }

  .upload-area .icon {
    font-size: 36px;
    margin-bottom: 8px;
  }

  .upload-area p {
    font-size: 13px;
  }

  .form-group input,
  .form-group select,
  .form-group textarea {
    font-size: 16px;
    padding: 12px 14px;
  }

  .btn {
    padding: 12px 24px;
    font-size: 14px;
    width: 100%;
    justify-content: center;
  }

  .file-info {
    padding: 12px;
    gap: 10px;
  }

  .file-info .fi-icon {
    font-size: 24px;
  }

  .file-info .fi-name {
    font-size: 13px;
  }

  .preview-grid {
    grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
    gap: 6px;
  }

  .preview-item {
    padding: 6px;
    border-radius: 8px;
  }

  .preview-item .page-num {
    font-size: 10px;
  }

  .result-box {
    padding: 16px;
  }

  .result-box .icon {
    font-size: 28px;
  }

  .result-box p {
    font-size: 13px;
  }

  .sign-canvas-wrap {
    border-radius: 8px;
  }

  .file-list-item {
    padding: 10px;
    gap: 8px;
  }

  .file-list-item .fli-name {
    font-size: 12px;
  }

  .footer {
    padding: 20px 16px;
    font-size: 12px;
  }
}