/* ===== CSS Custom Properties ===== */
:root {
    /* Colors - Dark Theme (default) */
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-card: #16161f;
    --bg-card-hover: #1c1c28;
    --bg-input: #1a1a26;
    --bg-overlay: rgba(0, 0, 0, 0.6);

    --border-subtle: rgba(255, 255, 255, 0.06);
    --border-medium: rgba(255, 255, 255, 0.1);
    --border-accent: rgba(139, 92, 246, 0.3);

    --text-primary: #f0f0f5;
    --text-secondary: #8b8b9e;
    --text-tertiary: #5a5a6e;
    --text-inverse: #0a0a0f;

    --accent-1: #8b5cf6;
    --accent-2: #a78bfa;
    --accent-3: #c084fc;
    --accent-glow: rgba(139, 92, 246, 0.15);
    --accent-glow-strong: rgba(139, 92, 246, 0.3);

    --signal-positive: #34d399;
    --signal-negative: #f87171;
    --signal-zero: #fbbf24;
    --signal-grid: rgba(255, 255, 255, 0.04);
    --signal-axis: rgba(255, 255, 255, 0.12);
    --signal-text: rgba(255, 255, 255, 0.5);
    --signal-bg: #0f0f18;
    --signal-bit-bg: rgba(139, 92, 246, 0.08);

    --success: #34d399;
    --warning: #fbbf24;
    --error: #f87171;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 20px var(--accent-glow);

    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    --radius-xl: 20px;

    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* Light Theme */
[data-theme="light"] {
    --bg-primary: #f5f5fa;
    --bg-secondary: #ebebf0;
    --bg-card: #ffffff;
    --bg-card-hover: #f8f8fc;
    --bg-input: #f0f0f6;
    --bg-overlay: rgba(0, 0, 0, 0.3);

    --border-subtle: rgba(0, 0, 0, 0.06);
    --border-medium: rgba(0, 0, 0, 0.1);
    --border-accent: rgba(139, 92, 246, 0.25);

    --text-primary: #1a1a2e;
    --text-secondary: #6b6b80;
    --text-tertiary: #9b9bae;
    --text-inverse: #f0f0f5;

    --accent-glow: rgba(139, 92, 246, 0.08);
    --accent-glow-strong: rgba(139, 92, 246, 0.15);

    --signal-grid: rgba(0, 0, 0, 0.04);
    --signal-axis: rgba(0, 0, 0, 0.12);
    --signal-text: rgba(0, 0, 0, 0.45);
    --signal-bg: #fafaff;
    --signal-bit-bg: rgba(139, 92, 246, 0.06);
    --signal-positive: #059669;
    --signal-negative: #dc2626;
    --signal-zero: #d97706;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.1);
    --shadow-glow: 0 0 20px var(--accent-glow);
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}

/* ===== App Container ===== */
.app-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ===== Header ===== */
.app-header {
    position: sticky;
    top: 0;
    z-index: 100;
    padding: 16px 0;
    background: rgba(10, 10, 15, 0.8);
    backdrop-filter: blur(20px) saturate(1.5);
    border-bottom: 1px solid var(--border-subtle);
    margin: 0 -20px;
    padding-left: 20px;
    padding-right: 20px;
}

[data-theme="light"] .app-header {
    background: rgba(245, 245, 250, 0.85);
}

.header-glow {
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 400px;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--accent-1), transparent);
    opacity: 0.5;
}

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

.logo-group {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-icon {
    width: 40px;
    height: 40px;
    flex-shrink: 0;
}

.logo-text h1 {
    font-size: 1.25rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, var(--accent-2), var(--accent-3));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.2;
}

.logo-subtitle {
    font-size: 0.7rem;
    color: var(--text-tertiary);
    font-weight: 500;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.header-actions {
    display: flex;
    gap: 8px;
}

/* ===== Buttons ===== */
.btn-icon {
    width: 36px;
    height: 36px;
    border: 1px solid var(--border-medium);
    border-radius: var(--radius-sm);
    background: var(--bg-card);
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.btn-icon svg {
    width: 18px;
    height: 18px;
}

.btn-icon:hover {
    border-color: var(--accent-1);
    color: var(--accent-2);
    background: var(--accent-glow);
}

.icon-moon { display: none; }
[data-theme="light"] .icon-sun { display: none; }
[data-theme="light"] .icon-moon { display: block; }

.btn-sm {
    padding: 6px 12px;
    border: 1px solid var(--border-medium);
    border-radius: var(--radius-sm);
    background: var(--bg-card);
    color: var(--text-secondary);
    font-family: var(--font-sans);
    font-size: 0.75rem;
    font-weight: 600;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 5px;
    transition: all var(--transition-fast);
    white-space: nowrap;
}

.btn-sm svg {
    width: 14px;
    height: 14px;
}

.btn-sm:hover {
    border-color: var(--accent-1);
    color: var(--accent-2);
    background: var(--accent-glow);
}

.btn-random:hover { border-color: var(--success); color: var(--success); }
.btn-clear:hover { border-color: var(--error); color: var(--error); }
.btn-export:hover { border-color: var(--accent-1); color: var(--accent-2); }

/* ===== Input Section ===== */
.input-section {
    margin-top: 24px;
}

.input-card {
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    padding: 20px;
    box-shadow: var(--shadow-md);
}

.input-card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
}

.section-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--accent-2);
    background: var(--accent-glow);
    padding: 5px 12px;
    border-radius: 100px;
    border: 1px solid var(--border-accent);
}

.section-badge svg {
    width: 14px;
    height: 14px;
}

.clock-rate-control {
    display: flex;
    align-items: center;
    gap: 10px;
}

.clock-rate-control label {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.clock-rate-wrapper {
    display: flex;
    align-items: center;
    gap: 2px;
    background: var(--bg-input);
    border: 1px solid var(--border-medium);
    border-radius: var(--radius-sm);
    padding: 2px;
}

.clock-btn {
    width: 28px;
    height: 28px;
    border: none;
    border-radius: 4px;
    background: transparent;
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 700;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.clock-btn:hover {
    background: var(--accent-glow);
    color: var(--accent-2);
}

.clock-rate-value {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-primary);
    min-width: 24px;
    text-align: center;
}

.clock-unit {
    font-size: 0.7rem;
    color: var(--text-tertiary);
    font-weight: 600;
    padding-right: 8px;
}

.input-field-group {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.input-wrapper {
    display: flex;
    align-items: center;
    background: var(--bg-input);
    border: 2px solid var(--border-medium);
    border-radius: var(--radius-md);
    padding: 4px;
    transition: border-color var(--transition-fast);
}

.input-wrapper:focus-within {
    border-color: var(--accent-1);
    box-shadow: var(--shadow-glow);
}

.input-prefix {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-tertiary);
    padding: 8px 4px 8px 12px;
    user-select: none;
}

.binary-input {
    flex: 1;
    border: none;
    background: transparent;
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 1.1rem;
    font-weight: 600;
    letter-spacing: 0.15em;
    padding: 8px 4px;
    outline: none;
    min-width: 0;
}

.binary-input::placeholder {
    color: var(--text-tertiary);
    font-weight: 400;
    letter-spacing: 0.05em;
}

.input-actions {
    display: flex;
    gap: 6px;
    padding-right: 4px;
    flex-shrink: 0;
}

.bit-display {
    display: flex;
    gap: 4px;
    flex-wrap: wrap;
    min-height: 0;
}

.bit-display:empty {
    display: none;
}

.bit-chip {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    font-weight: 700;
    padding: 4px 10px;
    border-radius: 6px;
    border: 1px solid var(--border-medium);
    transition: all var(--transition-fast);
    animation: bitAppear 0.2s ease-out both;
}

.bit-chip.bit-1 {
    background: rgba(139, 92, 246, 0.12);
    border-color: rgba(139, 92, 246, 0.25);
    color: var(--accent-2);
}

.bit-chip.bit-0 {
    background: var(--bg-input);
    color: var(--text-secondary);
}

@keyframes bitAppear {
    from { opacity: 0; transform: scale(0.8) translateY(4px); }
    to { opacity: 1; transform: scale(1) translateY(0); }
}

/* ===== Encoding Section ===== */
.encoding-section {
    margin-top: 20px;
}

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

.encoding-actions {
    display: flex;
    gap: 6px;
}

.encoding-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 8px;
}

.encoding-chip {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 14px;
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    user-select: none;
    position: relative;
    overflow: hidden;
}

.encoding-chip::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, var(--accent-glow), transparent);
    opacity: 0;
    transition: opacity var(--transition-fast);
}

.encoding-chip:hover {
    border-color: var(--border-medium);
    background: var(--bg-card-hover);
}

.encoding-chip:hover::before {
    opacity: 1;
}

.encoding-chip.active {
    border-color: var(--accent-1);
    background: var(--accent-glow);
    box-shadow: var(--shadow-glow);
}

.encoding-chip.active::before {
    opacity: 1;
}

.encoding-checkbox {
    width: 18px;
    height: 18px;
    border: 2px solid var(--border-medium);
    border-radius: 5px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: all var(--transition-fast);
    position: relative;
    z-index: 1;
}

.encoding-chip.active .encoding-checkbox {
    background: var(--accent-1);
    border-color: var(--accent-1);
}

.encoding-checkbox svg {
    width: 12px;
    height: 12px;
    stroke: white;
    stroke-width: 3;
    fill: none;
    opacity: 0;
    transform: scale(0.5);
    transition: all var(--transition-fast);
}

.encoding-chip.active .encoding-checkbox svg {
    opacity: 1;
    transform: scale(1);
}

.encoding-label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-primary);
    position: relative;
    z-index: 1;
    line-height: 1.3;
}

.encoding-category {
    font-size: 0.6rem;
    color: var(--text-tertiary);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

/* ===== Signals Section ===== */
.signals-section {
    margin-top: 24px;
    margin-bottom: 40px;
}

.signals-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
}

.signals-container {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

/* Empty State */
.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 60px 20px;
    text-align: center;
}

.empty-icon {
    width: 80px;
    height: 80px;
    color: var(--text-tertiary);
    margin-bottom: 16px;
    opacity: 0.4;
    animation: emptyPulse 3s ease-in-out infinite;
}

@keyframes emptyPulse {
    0%, 100% { opacity: 0.3; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.05); }
}

.empty-title {
    font-size: 1rem;
    font-weight: 700;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

.empty-desc {
    font-size: 0.8rem;
    color: var(--text-tertiary);
    max-width: 320px;
}

/* Signal Card */
.signal-card {
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
    animation: cardAppear 0.35s ease-out both;
}

.signal-card:hover {
    border-color: var(--border-medium);
    box-shadow: var(--shadow-md);
}

@keyframes cardAppear {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: translateY(0); }
}

.signal-card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 16px;
    border-bottom: 1px solid var(--border-subtle);
}

.signal-title-group {
    display: flex;
    align-items: center;
    gap: 10px;
}

.signal-color-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    flex-shrink: 0;
}

.signal-title {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text-primary);
}

.signal-category-tag {
    font-size: 0.6rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    padding: 2px 8px;
    border-radius: 100px;
    background: var(--accent-glow);
    color: var(--accent-2);
    border: 1px solid var(--border-accent);
}

.signal-card-actions {
    display: flex;
    gap: 4px;
}

.signal-canvas-wrapper {
    padding: 8px;
}

.signal-canvas {
    width: 100%;
    display: block;
    border-radius: var(--radius-sm);
}

/* Signal description */
.signal-description {
    padding: 8px 16px 12px;
    font-size: 0.72rem;
    color: var(--text-tertiary);
    line-height: 1.5;
    border-top: 1px solid var(--border-subtle);
}

/* ===== Modal ===== */
.modal-overlay {
    position: fixed;
    inset: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-overlay);
    backdrop-filter: blur(8px);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

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

.modal-card {
    width: 90%;
    max-width: 560px;
    max-height: 80vh;
    background: var(--bg-card);
    border: 1px solid var(--border-medium);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    transform: scale(0.95) translateY(10px);
    transition: transform var(--transition-base);
}

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

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 24px;
    border-bottom: 1px solid var(--border-subtle);
}

.modal-header h2 {
    font-size: 1.1rem;
    font-weight: 800;
}

.modal-close {
    border: none;
    background: none;
}

.modal-body {
    padding: 20px 24px;
    overflow-y: auto;
    font-size: 0.85rem;
    line-height: 1.7;
    color: var(--text-secondary);
}

.modal-body h3 {
    color: var(--text-primary);
    font-size: 0.9rem;
    font-weight: 700;
    margin: 20px 0 10px;
}

.modal-body h3:first-of-type {
    margin-top: 14px;
}

.modal-body ol {
    padding-left: 20px;
}

.modal-body ol li {
    margin-bottom: 4px;
}

.encoding-info-grid {
    display: grid;
    gap: 6px;
}

.encoding-info-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 12px;
    background: var(--bg-input);
    border-radius: var(--radius-sm);
    font-size: 0.78rem;
}

.encoding-info-item strong {
    color: var(--text-primary);
    font-weight: 600;
}

.encoding-info-item span {
    color: var(--text-tertiary);
    font-size: 0.72rem;
}

/* ===== Responsive ===== */
@media (max-width: 640px) {
    .app-container { padding: 0 12px; }
    .app-header { margin: 0 -12px; padding-left: 12px; padding-right: 12px; }

    .input-card-header { flex-direction: column; align-items: flex-start; gap: 10px; }
    .input-wrapper { flex-wrap: wrap; }
    .input-actions { width: 100%; justify-content: flex-end; padding: 4px; }
    .binary-input { font-size: 0.95rem; }
    .encoding-grid { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); }
    .encoding-info-item { flex-direction: column; align-items: flex-start; gap: 2px; }

    .signal-card-header { flex-direction: column; align-items: flex-start; gap: 8px; }
}

/* ===== Scrollbar ===== */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border-medium); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-tertiary); }