/* ============================
   StegaCrypt — Global Styles
   ============================ */
:root {
    --bg-primary: #06060f;
    --bg-secondary: #0c0c1d;
    --bg-card: rgba(255, 255, 255, 0.03);
    --bg-card-hover: rgba(255, 255, 255, 0.06);
    --border: rgba(255, 255, 255, 0.08);
    --border-hover: rgba(0, 212, 255, 0.3);
    --text-primary: #f0f0f5;
    --text-secondary: rgba(240, 240, 245, 0.6);
    --text-muted: rgba(240, 240, 245, 0.35);
    --accent-cyan: #00d4ff;
    --accent-green: #00f5a0;
    --accent-purple: #a855f7;
    --accent-red: #ff4466;
    --gradient-primary: linear-gradient(135deg, #00d4ff, #00f5a0);
    --gradient-purple: linear-gradient(135deg, #a855f7, #00d4ff);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;
    --font-sans: 'Inter', -apple-system, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
}

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

html {
    scroll-behavior: smooth;
}

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

a { color: inherit; text-decoration: none; }

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

/* Matrix Background */
#matrix-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    pointer-events: none;
    opacity: 0.15;
}

/* ============================
   Navigation
   ============================ */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    padding: 16px 32px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: rgba(6, 6, 15, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.2rem;
}

.brand-icon {
    font-size: 1.4rem;
}

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

.nav-links a {
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover {
    color: var(--accent-cyan);
}

/* ============================
   Hero Section
   ============================ */
.hero {
    position: relative;
    z-index: 1;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 120px 24px 80px;
}

.hero-content {
    max-width: 800px;
}

.hero-badge {
    display: inline-block;
    padding: 8px 20px;
    background: rgba(0, 212, 255, 0.1);
    border: 1px solid rgba(0, 212, 255, 0.2);
    border-radius: 100px;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--accent-cyan);
    margin-bottom: 28px;
    animation: fadeInUp 0.8s ease;
}

.hero-title {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    font-weight: 900;
    line-height: 1.1;
    letter-spacing: -0.03em;
    margin-bottom: 24px;
    animation: fadeInUp 0.8s ease 0.1s both;
}

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

.hero-subtitle {
    font-size: 1.15rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto 40px;
    line-height: 1.7;
    animation: fadeInUp 0.8s ease 0.2s both;
}

.hero-actions {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin-bottom: 60px;
    animation: fadeInUp 0.8s ease 0.3s both;
}

.hero-stats {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 40px;
    animation: fadeInUp 0.8s ease 0.4s both;
}

.stat-value {
    display: block;
    font-size: 1.5rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

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

/* ============================
   Buttons
   ============================ */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    border-radius: var(--radius-md);
    font-family: var(--font-sans);
    font-size: 0.95rem;
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: var(--gradient-primary);
    color: #000;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(0, 212, 255, 0.3);
}

.btn-primary:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.btn-ghost {
    background: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.btn-ghost:hover {
    border-color: var(--accent-cyan);
    color: var(--accent-cyan);
}

.btn-full {
    width: 100%;
    justify-content: center;
    margin-top: 16px;
}

/* ============================
   Tool Section
   ============================ */
.tool-section {
    position: relative;
    z-index: 1;
    padding: 100px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 48px;
}

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 12px;
    letter-spacing: -0.02em;
}

.section-header p {
    color: var(--text-secondary);
    font-size: 1.05rem;
}

/* Mode Toggle */
.mode-toggle {
    display: flex;
    position: relative;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 4px;
    max-width: 320px;
    margin: 0 auto 40px;
}

.mode-btn {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    background: none;
    border: none;
    color: var(--text-secondary);
    font-family: var(--font-sans);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    border-radius: var(--radius-md);
    position: relative;
    z-index: 2;
    transition: color 0.3s;
}

.mode-btn.active {
    color: #000;
}

.mode-slider {
    position: absolute;
    top: 4px;
    left: 4px;
    width: calc(50% - 4px);
    height: calc(100% - 8px);
    background: var(--gradient-primary);
    border-radius: calc(var(--radius-lg) - 4px);
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 1;
}

.mode-toggle[data-active="decode"] .mode-slider {
    transform: translateX(100%);
}

/* Panels */
.panel {
    display: none;
    animation: fadeIn 0.4s ease;
}

.panel.active {
    display: block;
}

.panel-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.panel-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px;
}

.panel-card h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--text-secondary);
}

/* Dropzone */
.dropzone {
    border: 2px dashed var(--border);
    border-radius: var(--radius-md);
    padding: 48px 24px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
    position: relative;
    min-height: 250px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.dropzone:hover, .dropzone.dragover {
    border-color: var(--accent-cyan);
    background: rgba(0, 212, 255, 0.03);
}

.dropzone-content svg {
    color: var(--text-muted);
    margin-bottom: 16px;
}

.dropzone-content p {
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.dropzone-content .link {
    color: var(--accent-cyan);
    cursor: pointer;
}

.dropzone-hint {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.preview-img {
    max-width: 100%;
    max-height: 240px;
    border-radius: var(--radius-sm);
    object-fit: contain;
}

.hidden { display: none !important; }

/* Message Input */
.message-input {
    width: 100%;
    min-height: 150px;
    padding: 16px;
    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-sans);
    font-size: 0.95rem;
    resize: vertical;
    transition: border-color 0.3s;
    line-height: 1.6;
}

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

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

.char-counter {
    text-align: right;
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 8px;
    font-family: var(--font-mono);
}

/* Result Card */
.result-card {
    margin-top: 32px;
    background: var(--bg-card);
    border: 1px solid rgba(0, 245, 160, 0.2);
    border-radius: var(--radius-lg);
    padding: 32px;
    animation: slideUp 0.5s ease;
}

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

.result-badge {
    display: inline-block;
    padding: 8px 20px;
    background: rgba(0, 245, 160, 0.1);
    border: 1px solid rgba(0, 245, 160, 0.2);
    border-radius: 100px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--accent-green);
}

.result-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
    align-items: start;
}

.result-image-wrap {
    background: rgba(0, 0, 0, 0.3);
    border-radius: var(--radius-md);
    padding: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.result-image-wrap canvas {
    max-width: 100%;
    max-height: 300px;
    border-radius: var(--radius-sm);
}

.result-stats h4 {
    margin-bottom: 16px;
    font-size: 1rem;
    color: var(--text-secondary);
}

.stat-row {
    display: flex;
    justify-content: space-between;
    padding: 10px 0;
    border-bottom: 1px solid var(--border);
    font-size: 0.9rem;
}

.stat-row span:first-child {
    color: var(--text-secondary);
}

.stat-row span:last-child {
    font-weight: 600;
    font-family: var(--font-mono);
    color: var(--accent-cyan);
}

/* Binary Visualization */
.binary-viz {
    margin-top: 32px;
    padding-top: 32px;
    border-top: 1px solid var(--border);
}

.binary-viz h4 {
    margin-bottom: 4px;
}

.viz-subtitle {
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-bottom: 20px;
}

.pixel-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 8px;
}

.pixel-cell {
    background: rgba(0, 0, 0, 0.3);
    border-radius: var(--radius-sm);
    padding: 8px 12px;
    font-family: var(--font-mono);
    font-size: 0.7rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.pixel-color {
    width: 16px;
    height: 16px;
    border-radius: 4px;
    flex-shrink: 0;
}

.pixel-bits {
    color: var(--text-secondary);
}

.pixel-bits .modified {
    color: var(--accent-green);
    font-weight: 700;
}

/* Decode Output */
.decode-output {
    min-height: 200px;
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.decode-placeholder {
    text-align: center;
    color: var(--text-muted);
}

.decode-placeholder svg {
    margin-bottom: 12px;
    opacity: 0.4;
}

.decoded-badge {
    display: inline-block;
    padding: 6px 16px;
    background: rgba(0, 245, 160, 0.1);
    border: 1px solid rgba(0, 245, 160, 0.2);
    border-radius: 100px;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--accent-green);
    margin-bottom: 16px;
}

.decode-message {
    width: 100%;
}

.decode-message p {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--text-primary);
    word-break: break-word;
}

/* ============================
   How It Works Section
   ============================ */
.how-section {
    position: relative;
    z-index: 1;
    padding: 100px 0;
    background: var(--bg-secondary);
}

.steps-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.step-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 32px 24px;
    transition: all 0.3s;
    position: relative;
}

.step-card:hover {
    border-color: var(--border-hover);
    background: var(--bg-card-hover);
    transform: translateY(-4px);
}

.step-number {
    font-size: 3rem;
    font-weight: 900;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1;
    margin-bottom: 16px;
    opacity: 0.5;
}

.step-card h3 {
    font-size: 1.1rem;
    margin-bottom: 12px;
}

.step-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 16px;
}

.step-example {
    background: rgba(0, 0, 0, 0.3);
    border-radius: var(--radius-sm);
    padding: 12px 16px;
}

.step-example code {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--accent-cyan);
}

.highlight-bit {
    color: var(--accent-red);
    font-weight: 700;
}

.highlight-bit-new {
    color: var(--accent-green);
    font-weight: 700;
    background: rgba(0, 245, 160, 0.15);
    padding: 0 2px;
    border-radius: 2px;
}

/* ============================
   Concepts Section
   ============================ */
.concepts-section {
    position: relative;
    z-index: 1;
    padding: 100px 0;
}

.concepts-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}

.concept-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px 24px;
    transition: all 0.3s;
}

.concept-card:hover {
    border-color: var(--border-hover);
    transform: translateY(-4px);
}

.concept-icon {
    font-size: 2rem;
    margin-bottom: 16px;
}

.concept-card h3 {
    font-size: 1rem;
    margin-bottom: 10px;
}

.concept-card p {
    color: var(--text-secondary);
    font-size: 0.85rem;
    line-height: 1.6;
}

.concept-card code {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--accent-cyan);
    background: rgba(0, 212, 255, 0.1);
    padding: 2px 6px;
    border-radius: 4px;
}

/* ============================
   Footer
   ============================ */
.footer {
    position: relative;
    z-index: 1;
    padding: 48px 0;
    border-top: 1px solid var(--border);
    text-align: center;
}

.footer-brand {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-weight: 700;
    font-size: 1.2rem;
    margin-bottom: 12px;
}

.footer p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.footer-note {
    margin-top: 8px;
    color: var(--text-muted) !important;
    font-size: 0.8rem !important;
}

.footer-concepts {
    margin-top: 16px;
}

.footer-concepts p:first-child {
    color: var(--accent-cyan);
    font-weight: 600;
    font-size: 0.95rem;
    margin-bottom: 8px;
}

.footer-concepts p {
    color: var(--text-muted);
    font-size: 0.8rem;
    line-height: 1.8;
    letter-spacing: 0.03em;
}

/* ============================
   Animations
   ============================ */
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(24px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

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

/* ============================
   Responsive
   ============================ */
@media (max-width: 1024px) {
    .steps-grid, .concepts-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .navbar { padding: 12px 16px; }
    .nav-links { display: none; }
    .panel-grid, .result-grid {
        grid-template-columns: 1fr;
    }
    .hero-stats {
        flex-direction: column;
        gap: 16px;
    }
    .stat-divider { width: 40px; height: 1px; }
    .steps-grid, .concepts-grid {
        grid-template-columns: 1fr;
    }
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
}

/* Loading State */
.btn.loading {
    pointer-events: none;
    position: relative;
}

.btn.loading::after {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    border: 2px solid transparent;
    border-top-color: currentColor;
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
}

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