@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&family=JetBrains+Mono:wght@400;500;600&display=swap');

:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-card: rgba(255,255,255,0.03);
  --bg-card-hover: rgba(255,255,255,0.06);
  --bg-input: rgba(255,255,255,0.05);
  --border: rgba(255,255,255,0.08);
  --border-focus: rgba(139,92,246,0.5);
  --text-primary: #f0f0f5;
  --text-secondary: #8888a0;
  --text-muted: #55556a;
  --accent-1: #8b5cf6;
  --accent-2: #6366f1;
  --accent-3: #a78bfa;
  --gradient-1: linear-gradient(135deg, #8b5cf6, #6366f1);
  --gradient-2: linear-gradient(135deg, #6366f1, #3b82f6);
  --gradient-3: linear-gradient(135deg, #8b5cf6, #ec4899);
  --gradient-hero: linear-gradient(135deg, rgba(139,92,246,0.15), rgba(99,102,241,0.1), rgba(59,130,246,0.05));
  --success: #22c55e;
  --error: #ef4444;
  --warning: #f59e0b;
  --shadow: 0 4px 24px rgba(0,0,0,0.3);
  --shadow-lg: 0 8px 40px rgba(0,0,0,0.4);
  --radius: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="light"] {
  --bg-primary: #f5f5fa;
  --bg-secondary: #ffffff;
  --bg-card: rgba(0,0,0,0.02);
  --bg-card-hover: rgba(0,0,0,0.04);
  --bg-input: rgba(0,0,0,0.04);
  --border: rgba(0,0,0,0.08);
  --border-focus: rgba(139,92,246,0.5);
  --text-primary: #1a1a2e;
  --text-secondary: #6b6b80;
  --text-muted: #9999aa;
  --shadow: 0 4px 24px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 40px rgba(0,0,0,0.12);
  --gradient-hero: linear-gradient(135deg, rgba(139,92,246,0.08), rgba(99,102,241,0.05), rgba(59,130,246,0.03));
}

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

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

/* ===== NAVBAR ===== */
.navbar {
  position: sticky; top: 0; z-index: 100;
  background: rgba(10,10,15,0.8);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  padding: 0 2rem;
  height: 64px;
  display: flex; align-items: center; justify-content: space-between;
}
[data-theme="light"] .navbar { background: rgba(255,255,255,0.85); }

.navbar-brand {
  display: flex; align-items: center; gap: 10px;
  text-decoration: none; color: var(--text-primary);
  font-weight: 700; font-size: 1.2rem;
}
.navbar-brand .brand-icon {
  width: 36px; height: 36px; border-radius: 10px;
  background: var(--gradient-1);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem; color: #fff;
}
.nav-links {
  display: flex; align-items: center; gap: 4px;
  list-style: none;
}
.nav-links a {
  text-decoration: none; color: var(--text-secondary);
  padding: 8px 14px; border-radius: 8px;
  font-size: 0.88rem; font-weight: 500;
  transition: var(--transition);
}
.nav-links a:hover, .nav-links a.active {
  color: var(--text-primary);
  background: var(--bg-card-hover);
}
.nav-right { display: flex; align-items: center; gap: 12px; }

/* Theme Toggle */
.theme-toggle {
  width: 40px; height: 40px; border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer; display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem; transition: var(--transition);
}
.theme-toggle:hover {
  background: var(--bg-card-hover);
  color: var(--accent-1);
  border-color: var(--accent-1);
}

/* Mobile menu */
.menu-toggle {
  display: none; background: none; border: none;
  color: var(--text-primary); font-size: 1.4rem; cursor: pointer;
}

/* ===== HERO / LANDING ===== */
.hero {
  padding: 5rem 2rem 4rem;
  text-align: center;
  background: var(--gradient-hero);
  position: relative; overflow: hidden;
}
.hero::before {
  content: ''; position: absolute; top: -50%; left: -50%;
  width: 200%; height: 200%;
  background: radial-gradient(circle at 30% 50%, rgba(139,92,246,0.08) 0%, transparent 50%),
              radial-gradient(circle at 70% 50%, rgba(99,102,241,0.06) 0%, transparent 50%);
  animation: heroFloat 15s ease-in-out infinite;
}
@keyframes heroFloat {
  0%,100% { transform: translate(0,0) rotate(0); }
  50% { transform: translate(-2%,2%) rotate(1deg); }
}
.hero-content { position: relative; z-index: 1; max-width: 700px; margin: 0 auto; }
.hero-badge {
  display: inline-flex; align-items: center; gap: 6px;
  background: rgba(139,92,246,0.1); border: 1px solid rgba(139,92,246,0.2);
  padding: 6px 16px; border-radius: 50px;
  font-size: 0.8rem; color: var(--accent-3);
  margin-bottom: 1.5rem; font-weight: 500;
}
.hero h1 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 800; line-height: 1.15;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-3) 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero p {
  color: var(--text-secondary); font-size: 1.1rem;
  line-height: 1.6; max-width: 550px; margin: 0 auto 2rem;
}

/* ===== CIPHER CARDS GRID ===== */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.2rem; max-width: 1100px;
  margin: 0 auto; padding: 0 2rem 4rem;
}
.cipher-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.8rem;
  cursor: pointer; text-decoration: none; color: inherit;
  transition: var(--transition);
  position: relative; overflow: hidden;
}
.cipher-card::before {
  content: ''; position: absolute; top: 0; left: 0;
  width: 100%; height: 3px;
  background: var(--gradient-1);
  opacity: 0; transition: var(--transition);
}
.cipher-card:hover {
  transform: translateY(-4px);
  border-color: rgba(139,92,246,0.3);
  box-shadow: var(--shadow-lg);
  background: var(--bg-card-hover);
}
.cipher-card:hover::before { opacity: 1; }
.card-icon {
  width: 48px; height: 48px; border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.4rem; margin-bottom: 1rem;
}
.card-icon.c1 { background: rgba(139,92,246,0.12); color: #8b5cf6; }
.card-icon.c2 { background: rgba(99,102,241,0.12); color: #6366f1; }
.card-icon.c3 { background: rgba(236,72,153,0.12); color: #ec4899; }
.card-icon.c4 { background: rgba(59,130,246,0.12); color: #3b82f6; }
.card-icon.c5 { background: rgba(34,197,94,0.12); color: #22c55e; }
.cipher-card h3 { font-size: 1.1rem; font-weight: 600; margin-bottom: 0.5rem; }
.cipher-card p { color: var(--text-secondary); font-size: 0.88rem; line-height: 1.5; }

/* ===== PAGE CONTAINER ===== */
.page-container {
  max-width: 960px; margin: 0 auto;
  padding: 2rem 2rem 4rem;
}
.page-header {
  margin-bottom: 2rem;
  display: flex; align-items: center; gap: 14px;
}
.page-header .back-btn {
  width: 40px; height: 40px; border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer; display: flex; align-items: center; justify-content: center;
  text-decoration: none; font-size: 1.1rem;
  transition: var(--transition);
}
.page-header .back-btn:hover {
  background: var(--bg-card-hover);
  color: var(--accent-1);
}
.page-header h1 {
  font-size: 1.6rem; font-weight: 700;
}
.page-header .algo-badge {
  background: rgba(139,92,246,0.1);
  color: var(--accent-3);
  padding: 4px 12px; border-radius: 50px;
  font-size: 0.75rem; font-weight: 600;
  margin-left: auto;
}

/* ===== FORM SECTIONS ===== */
.form-section {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}
.form-section h2 {
  font-size: 1rem; font-weight: 600;
  margin-bottom: 1rem;
  display: flex; align-items: center; gap: 8px;
}
.form-section h2 .section-icon {
  width: 28px; height: 28px; border-radius: 8px;
  background: rgba(139,92,246,0.1);
  color: var(--accent-1);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.85rem;
}
.form-group { margin-bottom: 1rem; }
.form-group label {
  display: block; font-size: 0.85rem; font-weight: 500;
  color: var(--text-secondary); margin-bottom: 6px;
}
.form-group input, .form-group textarea, .form-group select {
  width: 100%; padding: 10px 14px;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: 10px; color: var(--text-primary);
  font-family: 'Inter', sans-serif; font-size: 0.9rem;
  transition: var(--transition);
  outline: none;
}
.form-group textarea {
  min-height: 100px; resize: vertical;
  font-family: 'JetBrains Mono', monospace;
}
.form-group input:focus, .form-group textarea:focus, .form-group select:focus {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(139,92,246,0.1);
}
.form-group .hint {
  font-size: 0.78rem; color: var(--text-muted);
  margin-top: 4px;
}

/* Mode Toggle */
.mode-toggle {
  display: flex; gap: 4px;
  background: var(--bg-input);
  border-radius: 10px; padding: 4px;
  margin-bottom: 1rem;
}
.mode-toggle button {
  flex: 1; padding: 10px; border: none;
  background: transparent; color: var(--text-secondary);
  border-radius: 8px; cursor: pointer;
  font-weight: 600; font-size: 0.88rem;
  font-family: 'Inter', sans-serif;
  transition: var(--transition);
}
.mode-toggle button.active {
  background: var(--gradient-1);
  color: #fff;
  box-shadow: 0 2px 12px rgba(139,92,246,0.3);
}

/* Matrix Input */
.matrix-grid {
  display: inline-grid; gap: 6px;
  margin: 0.5rem 0;
}
.matrix-grid.size-2 { grid-template-columns: repeat(2, 70px); }
.matrix-grid.size-3 { grid-template-columns: repeat(3, 70px); }
.matrix-grid input {
  width: 70px; height: 44px; text-align: center;
  font-family: 'JetBrains Mono', monospace;
  font-weight: 600; font-size: 1rem;
}
.matrix-wrapper {
  display: flex; align-items: center; gap: 12px;
}
.matrix-bracket {
  font-size: 3rem; font-weight: 100;
  color: var(--accent-1); line-height: 1;
}

/* Buttons */
.btn-primary {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 28px;
  background: var(--gradient-1);
  color: #fff; border: none; border-radius: 10px;
  font-family: 'Inter', sans-serif;
  font-weight: 600; font-size: 0.95rem;
  cursor: pointer; transition: var(--transition);
  box-shadow: 0 2px 12px rgba(139,92,246,0.3);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 20px rgba(139,92,246,0.4);
}
.btn-primary:active { transform: translateY(0); }
.btn-primary:disabled {
  opacity: 0.5; cursor: not-allowed;
  transform: none !important;
}

.btn-secondary {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 10px 20px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-secondary); border-radius: 10px;
  font-family: 'Inter', sans-serif;
  font-weight: 500; font-size: 0.88rem;
  cursor: pointer; transition: var(--transition);
}
.btn-secondary:hover {
  background: var(--bg-card-hover);
  color: var(--text-primary);
  border-color: var(--accent-1);
}
.btn-danger {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 10px 20px;
  background: rgba(239,68,68,0.1);
  border: 1px solid rgba(239,68,68,0.2);
  color: var(--error); border-radius: 10px;
  font-family: 'Inter', sans-serif;
  font-weight: 500; font-size: 0.88rem;
  cursor: pointer; transition: var(--transition);
}
.btn-danger:hover { background: rgba(239,68,68,0.2); }

/* ===== RESULT SECTION ===== */
.result-section {
  display: none;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin-top: 1.5rem;
  animation: fadeSlideUp 0.4s ease;
}
.result-section.visible { display: block; }

@keyframes fadeSlideUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

.result-output {
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem;
  margin-bottom: 1rem;
  font-family: 'JetBrains Mono', monospace;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--accent-3);
  word-break: break-all;
  position: relative;
}
.result-output .copy-btn {
  position: absolute; top: 8px; right: 8px;
  width: 32px; height: 32px; border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-muted);
  cursor: pointer; font-size: 0.85rem;
  display: flex; align-items: center; justify-content: center;
  transition: var(--transition);
}
.result-output .copy-btn:hover { color: var(--accent-1); border-color: var(--accent-1); }

.result-formula {
  background: rgba(139,92,246,0.08);
  border: 1px solid rgba(139,92,246,0.15);
  border-radius: 10px;
  padding: 0.8rem 1rem;
  margin-bottom: 1rem;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.9rem;
  color: var(--accent-3);
}

/* Steps */
.steps-container { margin-top: 1rem; }
.steps-header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 0.8rem;
  cursor: pointer;
  padding: 0.5rem 0;
}
.steps-header h3 {
  font-size: 0.95rem; font-weight: 600;
  display: flex; align-items: center; gap: 8px;
}
.steps-header .toggle-icon {
  transition: transform 0.3s;
  color: var(--text-muted);
}
.steps-header .toggle-icon.open { transform: rotate(180deg); }

.steps-list { display: flex; flex-direction: column; gap: 6px; }
.step-item {
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 14px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.82rem;
  line-height: 1.5;
  color: var(--text-secondary);
  animation: stepFadeIn 0.3s ease forwards;
  opacity: 0;
}
@keyframes stepFadeIn {
  from { opacity: 0; transform: translateX(-8px); }
  to { opacity: 1; transform: translateX(0); }
}
.step-item .step-num {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 22px; height: 22px;
  background: var(--gradient-1);
  color: #fff; border-radius: 6px;
  font-size: 0.72rem; font-weight: 700;
  margin-right: 8px;
}
.step-item .step-highlight {
  color: var(--accent-3); font-weight: 600;
}

/* Matrix Display */
.matrix-display {
  display: inline-grid; gap: 2px;
  margin: 0.5rem 0;
  background: var(--bg-input);
  border-radius: 10px;
  padding: 1rem;
  border: 1px solid var(--border);
}
.matrix-display.m2 { grid-template-columns: repeat(2, 50px); }
.matrix-display.m3 { grid-template-columns: repeat(3, 50px); }
.matrix-display.m5 { grid-template-columns: repeat(5, 42px); }
.matrix-display .cell {
  display: flex; align-items: center; justify-content: center;
  height: 42px;
  background: rgba(139,92,246,0.08);
  border-radius: 6px;
  font-family: 'JetBrains Mono', monospace;
  font-weight: 600; font-size: 0.9rem;
  color: var(--text-primary);
  transition: var(--transition);
}
.matrix-display .cell.highlight {
  background: rgba(139,92,246,0.25);
  color: var(--accent-3);
  box-shadow: 0 0 0 2px rgba(139,92,246,0.3);
}

/* ===== HISTORY TABLE ===== */
.history-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}
.history-table th {
  text-align: left;
  padding: 12px 14px;
  color: var(--text-muted);
  font-weight: 600;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  border-bottom: 1px solid var(--border);
}
.history-table td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--border);
  color: var(--text-secondary);
}
.history-table tr:hover td {
  background: var(--bg-card-hover);
}
.history-table .algo-tag {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 50px;
  font-size: 0.75rem;
  font-weight: 600;
  background: rgba(139,92,246,0.1);
  color: var(--accent-3);
}
.history-table .mode-tag {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 50px;
  font-size: 0.75rem;
  font-weight: 600;
}
.mode-tag.encrypt { background: rgba(34,197,94,0.1); color: var(--success); }
.mode-tag.decrypt { background: rgba(59,130,246,0.1); color: #3b82f6; }

.empty-state {
  text-align: center; padding: 4rem 2rem;
  color: var(--text-muted);
}
.empty-state .empty-icon { font-size: 3rem; margin-bottom: 1rem; opacity: 0.3; }
.empty-state p { font-size: 0.95rem; }

/* ===== ERROR ===== */
.error-msg {
  background: rgba(239,68,68,0.08);
  border: 1px solid rgba(239,68,68,0.2);
  border-radius: 10px;
  padding: 12px 16px;
  color: var(--error);
  font-size: 0.88rem;
  margin-top: 1rem;
  display: none;
  animation: fadeSlideUp 0.3s ease;
}
.error-msg.visible { display: flex; align-items: center; gap: 8px; }

/* ===== LOADING ===== */
.loading-spinner {
  display: none; align-items: center; justify-content: center;
  gap: 8px; padding: 1rem;
  color: var(--text-muted); font-size: 0.88rem;
}
.loading-spinner.visible { display: flex; }
.spinner {
  width: 20px; height: 20px;
  border: 2px solid var(--border);
  border-top-color: var(--accent-1);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ===== FOOTER ===== */
.footer {
  text-align: center;
  padding: 2rem;
  color: var(--text-muted);
  font-size: 0.8rem;
  border-top: 1px solid var(--border);
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
  .navbar { padding: 0 1rem; }
  .nav-links {
    display: none;
    position: absolute; top: 64px; left: 0; right: 0;
    background: var(--bg-secondary);
    flex-direction: column;
    padding: 1rem;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow);
  }
  .nav-links.open { display: flex; }
  .menu-toggle { display: flex; }
  .hero { padding: 3rem 1.5rem 2.5rem; }
  .cards-grid { padding: 0 1rem 3rem; }
  .page-container { padding: 1.5rem 1rem 3rem; }
  .matrix-grid input { width: 56px; height: 40px; font-size: 0.9rem; }
  .matrix-grid.size-2 { grid-template-columns: repeat(2, 56px); }
  .matrix-grid.size-3 { grid-template-columns: repeat(3, 56px); }
  .history-table { font-size: 0.78rem; }
  .history-table th, .history-table td { padding: 8px; }
}

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-primary); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--accent-1); }