/* ============================================
   DBE Error Solver — Modern Dark Theme
   ============================================ */

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

:root {
    --bg-primary: #0a0a0f;
    --bg-secondary: #111119;
    --bg-card: rgba(17, 17, 25, 0.7);
    --bg-card-hover: rgba(25, 25, 40, 0.8);
    --bg-glass: rgba(255, 255, 255, 0.03);
    --border: rgba(255, 255, 255, 0.06);
    --border-hover: rgba(255, 255, 255, 0.12);
    --text-primary: #f0f0f5;
    --text-secondary: #8888a0;
    --text-muted: #555566;
    --accent: #7c5cff;
    --accent-light: #9b7fff;
    --accent-glow: rgba(124, 92, 255, 0.3);
    --accent-gradient: linear-gradient(135deg, #7c5cff, #00d4ff);
    --success: #00d48a;
    --success-glow: rgba(0, 212, 138, 0.2);
    --warning: #ffb84d;
    --error: #ff4d6a;
    --error-glow: rgba(255, 77, 106, 0.15);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.2);
    --shadow-md: 0 8px 32px rgba(0,0,0,0.3);
    --shadow-lg: 0 16px 64px rgba(0,0,0,0.4);
    --shadow-glow: 0 0 40px var(--accent-glow);
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

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

a:hover {
    color: var(--text-primary);
}

::selection {
    background: var(--accent);
    color: white;
}

/* --- Background Animation --- */
.bg-animation {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    pointer-events: none;
}

#particleCanvas {
    width: 100%;
    height: 100%;
}

/* --- Container --- */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* --- Navigation --- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 16px 0;
    background: rgba(10, 10, 15, 0.6);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transition: all var(--transition);
}

.navbar.scrolled {
    padding: 10px 0;
    background: rgba(10, 10, 15, 0.9);
}

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

.nav-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--text-primary);
}

.nav-logo-img {
    width: 36px;
    height: 36px;
    border-radius: 10px;
}

.nav-logo-text {
    font-size: 1.1rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.nav-logo-text .accent {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav-link {
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    transition: color var(--transition);
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-gradient);
    transition: width var(--transition);
    border-radius: 1px;
}

.nav-link:hover::after {
    width: 100%;
}

.nav-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 20px;
    background: var(--accent);
    color: white !important;
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    font-weight: 600;
    transition: all var(--transition);
}

.nav-btn:hover {
    background: var(--accent-light);
    transform: translateY(-1px);
    box-shadow: var(--shadow-glow);
}

.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.mobile-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-secondary);
    border-radius: 2px;
    transition: all var(--transition);
}

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 28px;
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-weight: 600;
    font-family: var(--font-sans);
    border: none;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
    white-space: nowrap;
}

.btn-primary {
    background: var(--accent);
    color: white;
    box-shadow: 0 4px 20px var(--accent-glow);
}

.btn-primary:hover {
    background: var(--accent-light);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 8px 32px var(--accent-glow);
}

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

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.06);
    color: var(--text-primary);
    border-color: var(--border-hover);
    transform: translateY(-2px);
}

.btn-ghost {
    background: transparent;
    color: var(--text-secondary);
    padding: 8px 16px;
    font-size: 0.85rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
}

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

/* --- Hero --- */
.hero {
    position: relative;
    z-index: 1;
    min-height: 100vh;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 120px 24px 80px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 16px;
    background: rgba(124, 92, 255, 0.1);
    border: 1px solid rgba(124, 92, 255, 0.2);
    border-radius: 100px;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--accent-light);
    margin-bottom: 24px;
    animation: fadeInUp 0.6s ease;
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 800;
    line-height: 1.1;
    letter-spacing: -0.03em;
    margin-bottom: 20px;
    animation: fadeInUp 0.6s ease 0.1s both;
}

.gradient-text {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 480px;
    line-height: 1.7;
    margin-bottom: 32px;
    animation: fadeInUp 0.6s ease 0.2s both;
}

.hero-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
    margin-bottom: 48px;
    animation: fadeInUp 0.6s ease 0.3s both;
}

.hero-stats {
    display: flex;
    align-items: center;
    gap: 28px;
    animation: fadeInUp 0.6s ease 0.4s both;
}

.stat {
    text-align: center;
}

.stat-number {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--text-primary);
}

.stat-plus {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--accent-light);
}

.stat-label {
    display: block;
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-top: 2px;
}

.stat-divider {
    width: 1px;
    height: 40px;
    background: var(--border);
}

/* --- Terminal Window --- */
.hero-visual {
    animation: fadeInUp 0.8s ease 0.3s both;
}

.terminal-window {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.terminal-header {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 20px;
    background: rgba(255, 255, 255, 0.02);
    border-bottom: 1px solid var(--border);
}

.terminal-dots {
    display: flex;
    gap: 6px;
}

.dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.dot.red { background: #ff5f56; }
.dot.yellow { background: #ffbd2e; }
.dot.green { background: #27c93f; }

.terminal-title {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
}

.terminal-body {
    padding: 24px;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    min-height: 220px;
}

.terminal-line {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 12px;
}

.terminal-prompt {
    color: var(--accent-light);
    font-weight: 600;
}

.terminal-text {
    color: var(--text-primary);
}

.terminal-cursor {
    color: var(--accent);
    animation: blink 1s infinite;
}

@keyframes blink {
    0%, 50% { opacity: 1; }
    51%, 100% { opacity: 0; }
}

.terminal-output {
    color: var(--text-secondary);
    line-height: 1.8;
}

.terminal-output .success {
    color: var(--success);
}

.terminal-output .error-text {
    color: var(--error);
}

.terminal-output .info {
    color: var(--accent-light);
}

/* --- Section Styles --- */
.section-header {
    text-align: center;
    margin-bottom: 56px;
}

.section-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 16px;
    background: rgba(124, 92, 255, 0.08);
    border: 1px solid rgba(124, 92, 255, 0.15);
    border-radius: 100px;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--accent-light);
    margin-bottom: 20px;
}

.section-title {
    font-size: clamp(1.8rem, 3.5vw, 2.8rem);
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 16px;
}

.section-desc {
    font-size: 1.05rem;
    color: var(--text-secondary);
    max-width: 560px;
    margin: 0 auto;
    line-height: 1.7;
}

/* --- Solver Section --- */
.solver-section {
    position: relative;
    z-index: 1;
    padding: 100px 0;
}

.solver-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    backdrop-filter: blur(10px);
}

.solver-input-area {
    padding: 32px;
}

.input-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
}

.input-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: rgba(124, 92, 255, 0.1);
    border-radius: var(--radius-sm);
    color: var(--accent-light);
}

.error-textarea {
    width: 100%;
    min-height: 160px;
    max-height: 500px;
    padding: 20px;
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 0.88rem;
    line-height: 1.6;
    resize: none;
    transition: border-color var(--transition), box-shadow var(--transition), height 0.2s ease;
    outline: none;
    overflow-y: auto;
    field-sizing: content;
}

.error-textarea::placeholder {
    color: var(--text-muted);
}

.error-textarea:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.search-mode-toggle {
    display: flex;
    gap: 4px;
    margin-top: 12px;
    padding: 4px;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border);
    border-radius: 12px;
    width: fit-content;
}

.mode-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 7px 14px;
    border: none;
    border-radius: 9px;
    background: transparent;
    color: var(--text-muted);
    font-family: var(--font-primary);
    font-size: 0.8rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.25s ease;
    white-space: nowrap;
}

.mode-btn:hover {
    color: var(--text-secondary);
    background: rgba(255, 255, 255, 0.04);
}

.mode-btn.active {
    background: var(--primary);
    color: #fff;
    box-shadow: 0 2px 8px var(--primary-glow);
}

.mode-btn svg {
    flex-shrink: 0;
}

/* ── Image Upload Area ── */
.image-upload-area {
    margin-top: 10px;
}

.image-upload-bar {
    display: flex;
    align-items: center;
    gap: 10px;
}

.image-upload-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    background: rgba(255, 255, 255, 0.04);
    border: 1px dashed var(--border);
    border-radius: 9px;
    color: var(--text-muted);
    font-family: var(--font-primary);
    font-size: 0.8rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.25s ease;
}

.image-upload-btn:hover {
    color: var(--accent-light);
    border-color: rgba(124, 92, 255, 0.4);
    background: rgba(124, 92, 255, 0.08);
}

.image-upload-btn svg {
    flex-shrink: 0;
}

.image-upload-hint {
    color: var(--text-muted);
    font-size: 0.72rem;
    opacity: 0.6;
}

.image-preview-container {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-top: 10px;
}

.image-preview-container:empty {
    display: none;
}

.image-preview-item {
    position: relative;
    width: 72px;
    height: 72px;
    border-radius: 10px;
    overflow: hidden;
    border: 1px solid var(--border);
    background: rgba(0, 0, 0, 0.3);
    flex-shrink: 0;
}

.image-preview-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.image-preview-remove {
    position: absolute;
    top: 2px;
    right: 2px;
    width: 20px;
    height: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.7);
    border: none;
    border-radius: 50%;
    color: #fff;
    font-size: 14px;
    line-height: 1;
    cursor: pointer;
    opacity: 0;
    transition: opacity 0.2s ease;
}

.image-preview-item:hover .image-preview-remove {
    opacity: 1;
}

.solver-card.drag-over {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow), inset 0 0 40px rgba(124, 92, 255, 0.05);
}

.input-footer {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 16px;
    margin-top: 16px;
    flex-wrap: wrap;
}

.input-hints {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.hint-chip {
    padding: 6px 14px;
    background: var(--bg-glass);
    border: 1px solid var(--border);
    border-radius: 100px;
    color: var(--text-muted);
    font-size: 0.78rem;
    font-family: var(--font-sans);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
}

.hint-chip:hover {
    color: var(--accent-light);
    border-color: rgba(124, 92, 255, 0.3);
    background: rgba(124, 92, 255, 0.06);
}

.btn-solve {
    padding: 14px 32px;
    font-size: 1rem;
    min-width: 180px;
    justify-content: center;
}

.btn-solve .btn-loader {
    display: flex;
    gap: 4px;
    align-items: center;
}

.loader-dot {
    width: 6px;
    height: 6px;
    background: white;
    border-radius: 50%;
    animation: dotPulse 1.4s ease-in-out infinite;
}

.loader-dot:nth-child(2) { animation-delay: 0.2s; }
.loader-dot:nth-child(3) { animation-delay: 0.4s; }

@keyframes dotPulse {
    0%, 80%, 100% { transform: scale(0.6); opacity: 0.4; }
    40% { transform: scale(1); opacity: 1; }
}

/* --- Solution Area --- */
.solution-area {
    border-top: 1px solid var(--border);
    padding: 32px;
    animation: slideDown 0.5s ease;
}

@keyframes slideDown {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

.solution-header {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 24px;
}

.solution-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    background: var(--success-glow);
    border-radius: 50%;
    color: var(--success);
}

.solution-title {
    font-size: 1.2rem;
    font-weight: 700;
}

.solution-confidence {
    font-size: 0.78rem;
    font-weight: 600;
    padding: 3px 10px;
    border-radius: 100px;
    margin-left: 8px;
}

.confidence-high {
    background: var(--success-glow);
    color: var(--success);
}

.confidence-medium {
    background: rgba(255, 184, 77, 0.15);
    color: var(--warning);
}

.confidence-low {
    background: var(--error-glow);
    color: var(--error);
}

.solution-content {
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 24px;
    margin-bottom: 20px;
}

.solution-content h4 {
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--accent-light);
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.solution-content p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 16px;
}

.solution-content .cause {
    padding: 12px 16px;
    background: var(--error-glow);
    border-left: 3px solid var(--error);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    margin-bottom: 20px;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.solution-content ol {
    padding-left: 20px;
    color: var(--text-secondary);
    line-height: 1.8;
}

.solution-content ol li {
    margin-bottom: 8px;
}

.solution-content ol li strong {
    color: var(--text-primary);
}

.solution-content code {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    padding: 2px 8px;
    background: rgba(124, 92, 255, 0.1);
    border-radius: 4px;
    color: var(--accent-light);
}

.solution-content .code-block {
    display: block;
    padding: 16px;
    background: rgba(0, 0, 0, 0.4);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    margin: 12px 0;
    overflow-x: auto;
    white-space: pre;
    font-family: var(--font-mono);
    font-size: 0.83rem;
    color: var(--text-primary);
}

.solution-footer {
    display: flex;
    gap: 12px;
}

/* --- Common Errors Section --- */
.errors-section {
    position: relative;
    z-index: 1;
    padding: 100px 0;
}

.error-filters {
    display: flex;
    gap: 8px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 40px;
}

.filter-btn {
    padding: 8px 20px;
    background: var(--bg-glass);
    border: 1px solid var(--border);
    border-radius: 100px;
    color: var(--text-muted);
    font-size: 0.85rem;
    font-weight: 500;
    font-family: var(--font-sans);
    cursor: pointer;
    transition: all var(--transition);
}

.filter-btn:hover {
    color: var(--text-primary);
    border-color: var(--border-hover);
}

.filter-btn.active {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
}

.errors-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 20px;
}

.error-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
    cursor: pointer;
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
}

.error-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--accent-gradient);
    opacity: 0;
    transition: opacity var(--transition);
}

.error-card:hover {
    background: var(--bg-card-hover);
    border-color: var(--border-hover);
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.error-card:hover::before {
    opacity: 1;
}

.error-card-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 12px;
}

.error-card-category {
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    padding: 3px 10px;
    border-radius: 100px;
    background: rgba(124, 92, 255, 0.1);
    color: var(--accent-light);
    white-space: nowrap;
}

.error-card-severity {
    font-size: 0.72rem;
    font-weight: 600;
    padding: 3px 10px;
    border-radius: 100px;
}

.severity-high {
    background: var(--error-glow);
    color: var(--error);
}

.severity-medium {
    background: rgba(255, 184, 77, 0.15);
    color: var(--warning);
}

.severity-low {
    background: var(--success-glow);
    color: var(--success);
}

.error-card-title {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 8px;
    font-family: var(--font-mono);
    color: var(--error);
    line-height: 1.4;
}

.error-card-desc {
    font-size: 0.88rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 16px;
}

.error-card-footer {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--accent-light);
    font-size: 0.82rem;
    font-weight: 500;
}

.error-card-footer svg {
    transition: transform var(--transition);
}

.error-card:hover .error-card-footer svg {
    transform: translateX(4px);
}

/* --- How It Works Section --- */
.how-section {
    position: relative;
    z-index: 1;
    padding: 100px 0;
}

.steps-grid {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0;
    flex-wrap: wrap;
}

.step-card {
    flex: 1;
    min-width: 240px;
    max-width: 320px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 32px 28px;
    text-align: center;
    transition: all var(--transition);
    position: relative;
}

.step-card:hover {
    background: var(--bg-card-hover);
    border-color: var(--border-hover);
    transform: translateY(-6px);
    box-shadow: var(--shadow-md);
}

.step-number {
    font-size: 3.5rem;
    font-weight: 900;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    opacity: 0.2;
    position: absolute;
    top: 16px;
    right: 20px;
    line-height: 1;
}

.step-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 60px;
    height: 60px;
    background: rgba(124, 92, 255, 0.1);
    border-radius: 16px;
    color: var(--accent-light);
    margin-bottom: 20px;
}

.step-card h3 {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 10px;
}

.step-card p {
    font-size: 0.88rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.step-connector {
    color: var(--text-muted);
    flex-shrink: 0;
    padding: 0 8px;
}

/* --- FAQ Section --- */
.faq-section {
    position: relative;
    z-index: 1;
    padding: 100px 0;
}

.faq-list {
    max-width: 720px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.faq-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: all var(--transition);
}

.faq-item:hover {
    border-color: var(--border-hover);
}

.faq-item.open {
    border-color: rgba(124, 92, 255, 0.2);
    background: var(--bg-card-hover);
}

.faq-question {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 24px;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 0.95rem;
    font-weight: 600;
    font-family: var(--font-sans);
    cursor: pointer;
    text-align: left;
    transition: color var(--transition);
}

.faq-question:hover {
    color: var(--accent-light);
}

.faq-chevron {
    transition: transform var(--transition);
    color: var(--text-muted);
    flex-shrink: 0;
}

.faq-item.open .faq-chevron {
    transform: rotate(180deg);
    color: var(--accent-light);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.4s ease;
}

.faq-item.open .faq-answer {
    max-height: 300px;
    padding: 0 24px 20px;
}

.faq-answer p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.7;
}

/* --- Footer --- */
.footer {
    position: relative;
    z-index: 1;
    padding: 80px 0 40px;
    border-top: 1px solid var(--border);
    background: rgba(0, 0, 0, 0.3);
}

.footer-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
    gap: 48px;
    margin-bottom: 48px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 16px;
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-primary);
}

.footer-logo-img {
    width: 32px;
    height: 32px;
    border-radius: 8px;
}

.footer-tagline {
    font-size: 0.88rem;
    color: var(--text-muted);
    line-height: 1.6;
    max-width: 300px;
}

.footer-links-group h4 {
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--text-secondary);
    margin-bottom: 16px;
}

.footer-links-group a {
    display: block;
    color: var(--text-muted);
    font-size: 0.88rem;
    padding: 4px 0;
    transition: color var(--transition);
}

.footer-links-group a:hover {
    color: var(--accent-light);
}

.footer-bottom {
    padding-top: 32px;
    border-top: 1px solid var(--border);
    text-align: center;
}

.footer-bottom p {
    font-size: 0.82rem;
    color: var(--text-muted);
}

/* --- Watermark --- */
.watermark {
    position: fixed;
    bottom: 20px;
    right: 20px;
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px 8px 12px;
    background: rgba(10, 10, 15, 0.6);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid rgba(124, 92, 255, 0.2);
    border-radius: 100px;
    color: var(--text-muted);
    font-family: var(--font-primary);
    font-size: 0.75rem;
    text-decoration: none;
    z-index: 999;
    transition: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

.watermark::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: 100px;
    background: linear-gradient(135deg, rgba(124, 92, 255, 0.05), rgba(0, 212, 255, 0.05));
    opacity: 0;
    transition: opacity 0.35s ease;
}

.watermark:hover {
    border-color: rgba(124, 92, 255, 0.5);
    color: var(--text-primary);
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(124, 92, 255, 0.2), 0 0 40px rgba(124, 92, 255, 0.05);
}

.watermark:hover::before {
    opacity: 1;
}

.watermark svg {
    flex-shrink: 0;
    color: var(--accent-light);
    opacity: 0.6;
    transition: opacity 0.35s ease;
}

.watermark:hover svg {
    opacity: 1;
}

.watermark-text {
    position: relative;
    letter-spacing: 0.02em;
}

.watermark-text strong {
    color: var(--accent-light);
    font-weight: 700;
}

/* --- Animations --- */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease;
}

.animate-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

/* --- Modal for Error Details --- */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(8px);
    z-index: 2000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    max-width: 640px;
    width: 100%;
    max-height: 80vh;
    overflow-y: auto;
    padding: 32px;
    transform: scale(0.95) translateY(10px);
    transition: transform 0.3s ease;
}

.modal-overlay.active .modal {
    transform: scale(1) translateY(0);
}

.modal-close {
    float: right;
    background: var(--bg-glass);
    border: 1px solid var(--border);
    border-radius: 50%;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--text-muted);
    transition: all var(--transition);
}

.modal-close:hover {
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.08);
}

.modal h3 {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 8px;
    padding-right: 48px;
    color: var(--error);
    font-family: var(--font-mono);
}

.modal .modal-category {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--accent-light);
    margin-bottom: 20px;
}

.modal .modal-body {
    margin-top: 20px;
}

.modal .modal-body h4 {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--accent-light);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    margin-bottom: 8px;
    margin-top: 20px;
}

.modal .modal-body h4:first-child {
    margin-top: 0;
}

.modal .modal-body p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.7;
}

.modal .modal-body ol {
    padding-left: 20px;
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.8;
}

.modal .modal-body ol li {
    margin-bottom: 6px;
}

.modal .modal-body ol li strong {
    color: var(--text-primary);
}

.modal .modal-body code {
    font-family: var(--font-mono);
    font-size: 0.83rem;
    padding: 2px 8px;
    background: rgba(124, 92, 255, 0.1);
    border-radius: 4px;
    color: var(--accent-light);
}

.modal .modal-body .code-block {
    display: block;
    padding: 14px;
    background: rgba(0, 0, 0, 0.4);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    margin: 12px 0;
    overflow-x: auto;
    white-space: pre;
    font-family: var(--font-mono);
    font-size: 0.82rem;
    color: var(--text-primary);
}

.modal .use-solver-btn {
    margin-top: 24px;
    width: 100%;
    justify-content: center;
}

/* --- Settings Panel --- */
.settings-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(8px);
    z-index: 3000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.settings-overlay.active {
    opacity: 1;
    visibility: visible;
}

.settings-panel {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    max-width: 540px;
    width: 100%;
    padding: 32px;
    transform: scale(0.95) translateY(10px);
    transition: transform 0.3s ease;
    max-height: 85vh;
    overflow-y: auto;
}

.settings-overlay.active .settings-panel {
    transform: scale(1) translateY(0);
}

.settings-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 12px;
}

.settings-header h3 {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-primary);
}

.settings-header h3 svg {
    color: var(--accent-light);
}

.settings-close {
    background: var(--bg-glass);
    border: 1px solid var(--border);
    border-radius: 50%;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--text-muted);
    transition: all var(--transition);
}

.settings-close:hover {
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.08);
}

.settings-desc {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 16px;
}

.settings-info-box {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 16px;
    background: rgba(124, 92, 255, 0.06);
    border: 1px solid rgba(124, 92, 255, 0.15);
    border-radius: var(--radius-md);
    margin-bottom: 20px;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.settings-info-box svg {
    flex-shrink: 0;
    color: var(--accent-light);
}

.settings-info-box a {
    color: var(--accent-light);
    font-weight: 600;
}

.settings-add-key {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

.settings-key-input {
    flex: 1;
    padding: 10px 16px;
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 0.85rem;
    outline: none;
    transition: all var(--transition);
}

.settings-key-input::placeholder {
    color: var(--text-muted);
}

.settings-key-input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.btn-sm {
    padding: 10px 20px;
    font-size: 0.85rem;
    white-space: nowrap;
}

.settings-key-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-bottom: 16px;
}

.key-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    transition: all var(--transition);
}

.key-item:hover {
    border-color: var(--border-hover);
}

.key-item.active-key {
    border-color: rgba(0, 212, 138, 0.3);
    background: rgba(0, 212, 138, 0.04);
}

.key-item-index {
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--text-muted);
    background: var(--bg-glass);
    padding: 3px 8px;
    border-radius: 4px;
    min-width: 28px;
    text-align: center;
}

.key-item.active-key .key-item-index {
    background: rgba(0, 212, 138, 0.15);
    color: var(--success);
}

.key-item-value {
    flex: 1;
    font-family: var(--font-mono);
    font-size: 0.83rem;
    color: var(--text-secondary);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.key-item-active-badge {
    font-size: 0.7rem;
    font-weight: 600;
    padding: 2px 8px;
    border-radius: 100px;
    background: var(--success-glow);
    color: var(--success);
    white-space: nowrap;
}

.key-item-remove {
    background: none;
    border: 1px solid transparent;
    border-radius: 6px;
    color: var(--text-muted);
    cursor: pointer;
    padding: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
}

.key-item-remove:hover {
    color: var(--error);
    border-color: var(--error-glow);
    background: var(--error-glow);
}

.settings-status {
    min-height: 20px;
    font-size: 0.82rem;
    margin-bottom: 12px;
}

.settings-status .status-success {
    color: var(--success);
}

.settings-status .status-error {
    color: var(--error);
}

.settings-model-section {
    margin-bottom: 16px;
}

.settings-label {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.settings-select {
    width: 100%;
    padding: 10px 14px;
    background: rgba(255,255,255,0.03);
    border: 1px solid var(--border);
    border-radius: 10px;
    color: var(--text-primary);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.82rem;
    outline: none;
    transition: border-color 0.3s, box-shadow 0.3s;
    appearance: none;
    -webkit-appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%238b8b9e' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    cursor: pointer;
}

.settings-select:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px var(--primary-glow);
}

.settings-select option {
    background: #1a1a2e;
    color: var(--text-primary);
}

.settings-model-hint {
    display: block;
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 6px;
}

.settings-test-btn {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    margin-bottom: 12px;
    padding: 10px;
    font-size: 0.85rem;
}

.settings-test-btn:disabled {
    opacity: 0.6;
    cursor: wait;
}

.settings-footer {
    padding-top: 16px;
    border-top: 1px solid var(--border);
}

.settings-note {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.78rem;
    color: var(--text-muted);
}

.settings-note svg {
    flex-shrink: 0;
    color: var(--success);
}

/* --- AI Status Bar --- */
.ai-status-bar {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 8px 18px;
    background: var(--bg-glass);
    border: 1px solid var(--border);
    border-radius: 100px;
    margin-top: 16px;
    font-size: 0.82rem;
    color: var(--text-secondary);
}

.ai-status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--text-muted);
    flex-shrink: 0;
}

.ai-status-dot.active {
    background: var(--success);
    box-shadow: 0 0 8px var(--success-glow);
    animation: pulse-dot 2s infinite;
}

.ai-status-dot.warning {
    background: var(--warning);
}

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

.ai-status-btn {
    background: rgba(124, 92, 255, 0.1);
    border: 1px solid rgba(124, 92, 255, 0.2);
    border-radius: 100px;
    color: var(--accent-light);
    font-size: 0.78rem;
    font-weight: 600;
    font-family: var(--font-sans);
    padding: 3px 12px;
    cursor: pointer;
    transition: all var(--transition);
}

.ai-status-btn:hover {
    background: rgba(124, 92, 255, 0.2);
    border-color: rgba(124, 92, 255, 0.4);
}

/* --- AI Source Badge in Solution --- */
.solution-source {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 4px 12px;
    border-radius: 100px;
    font-size: 0.72rem;
    font-weight: 600;
    margin-left: 8px;
}

.source-ai {
    background: rgba(124, 92, 255, 0.12);
    color: var(--accent-light);
    border: 1px solid rgba(124, 92, 255, 0.2);
}

.source-db {
    background: rgba(0, 212, 255, 0.1);
    color: #00d4ff;
    border: 1px solid rgba(0, 212, 255, 0.2);
}

.source-ai svg, .source-db svg {
    width: 12px;
    height: 12px;
}

.solution-model-tag {
    display: inline-flex;
    align-items: center;
    padding: 4px 10px;
    border-radius: 99px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.72rem;
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-muted);
    border: 1px solid var(--border);
}

/* --- Solution Images --- */
.solution-images {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 12px;
    margin-top: 12px;
}

.solution-image-wrap {
    margin: 0;
    border-radius: 10px;
    overflow: hidden;
    border: 1px solid var(--border);
    background: rgba(0, 0, 0, 0.2);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.solution-image-wrap:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.4);
}

.solution-image {
    width: 100%;
    height: auto;
    display: block;
    cursor: pointer;
    transition: opacity 0.2s ease;
}

.solution-image:hover {
    opacity: 0.85;
}

.solution-image-wrap figcaption {
    padding: 8px 12px;
    font-size: 0.78rem;
    color: var(--text-muted);
    text-align: center;
    border-top: 1px solid var(--border);
}

/* --- Image Viewer Lightbox --- */
.image-viewer-overlay {
    position: fixed;
    inset: 0;
    z-index: 10000;
    background: rgba(0, 0, 0, 0.92);
    backdrop-filter: blur(8px);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.image-viewer-overlay.active {
    opacity: 1;
    visibility: visible;
}

.image-viewer-close {
    position: absolute;
    top: 20px;
    right: 24px;
    background: none;
    border: none;
    color: #fff;
    font-size: 2rem;
    cursor: pointer;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: background 0.2s ease;
}

.image-viewer-close:hover {
    background: rgba(255, 255, 255, 0.1);
}

.image-viewer-img {
    max-width: 90vw;
    max-height: 80vh;
    border-radius: 12px;
    box-shadow: 0 8px 40px rgba(0, 0, 0, 0.5);
    object-fit: contain;
}

.image-viewer-caption {
    margin-top: 12px;
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.88rem;
}

/* --- AI Loading Text --- */
.ai-loading-text {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 16px;
    color: var(--text-secondary);
    font-size: 0.88rem;
}

.ai-loading-text .spinner {
    width: 18px;
    height: 18px;
    border: 2px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* Nav link button style (for API Keys) */
button.nav-link {
    background: none;
    border: none;
    cursor: pointer;
    font-family: var(--font-sans);
}

/* Empty key list state */
.key-list-empty {
    text-align: center;
    padding: 24px 16px;
    color: var(--text-muted);
    font-size: 0.85rem;
}

.key-list-empty svg {
    display: block;
    margin: 0 auto 10px;
    opacity: 0.3;
}

/* --- Scrollbar --- */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.2);
}

/* --- Responsive --- */
@media (max-width: 1024px) {
    .hero {
        grid-template-columns: 1fr;
        gap: 40px;
        text-align: center;
        padding-top: 100px;
    }

    .hero-subtitle {
        max-width: 100%;
    }

    .hero-actions {
        justify-content: center;
    }

    .hero-stats {
        justify-content: center;
    }

    .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: 32px;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        flex-direction: column;
        padding: 20px 24px;
        background: rgba(10, 10, 15, 0.95);
        backdrop-filter: blur(20px);
        border-bottom: 1px solid var(--border);
        gap: 16px;
    }

    .nav-links.open {
        display: flex;
    }

    .mobile-toggle {
        display: flex;
    }

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

    .steps-grid {
        flex-direction: column;
    }

    .step-connector {
        transform: rotate(90deg);
    }

    .input-footer {
        flex-direction: column;
        align-items: stretch;
    }

    .hero-title {
        font-size: 2.2rem;
    }

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 32px;
    }
}

@media (max-width: 480px) {
    .hero-stats {
        flex-direction: column;
        gap: 20px;
    }

    .stat-divider {
        width: 40px;
        height: 1px;
    }

    .input-hints {
        gap: 6px;
    }

    .hint-chip {
        font-size: 0.72rem;
        padding: 4px 10px;
    }
}