/* ===== CSS Variables & Reset ===== */
:root {
    --bg-primary: #0a0a1a;
    --bg-secondary: #12122a;
    --bg-card: rgba(20, 20, 50, 0.6);
    --glass-border: rgba(255, 255, 255, 0.08);
    --glass-bg: rgba(255, 255, 255, 0.04);
    --text-primary: #e8e8f0;
    --text-secondary: #9090b0;
    --text-muted: #606080;
    --accent-indigo: #6366f1;
    --accent-pink: #f472b6;
    --accent-green: #34d399;
    --accent-indigo-glow: rgba(99, 102, 241, 0.3);
    --accent-pink-glow: rgba(244, 114, 182, 0.3);
    --accent-green-glow: rgba(52, 211, 153, 0.3);
    --danger: #ef4444;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --shadow-glow: 0 0 30px rgba(99, 102, 241, 0.15);
    --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    overflow-x: hidden;
    line-height: 1.5;
}

/* ===== Ambient Background ===== */
.ambient-bg {
    position: fixed; inset: 0; z-index: 0; pointer-events: none; overflow: hidden;
}
.ambient-orb {
    position: absolute; border-radius: 50%; filter: blur(120px); opacity: 0.15;
    animation: orbFloat 20s ease-in-out infinite;
}
.orb-1 { width: 500px; height: 500px; background: var(--accent-indigo); top: -10%; left: -5%; animation-delay: 0s; }
.orb-2 { width: 400px; height: 400px; background: var(--accent-pink); bottom: -10%; right: -5%; animation-delay: -7s; }
.orb-3 { width: 350px; height: 350px; background: var(--accent-green); top: 40%; left: 50%; animation-delay: -14s; }

@keyframes orbFloat {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33% { transform: translate(30px, -30px) scale(1.05); }
    66% { transform: translate(-20px, 20px) scale(0.95); }
}

/* ===== Glass Effect ===== */
.glass {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
}

/* ===== Header ===== */
#main-header {
    position: sticky; top: 0; z-index: 100;
    background: rgba(10, 10, 26, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--glass-border);
    padding: 0 24px;
}
.header-content {
    max-width: 1600px; margin: 0 auto;
    display: flex; align-items: center; justify-content: space-between;
    height: 60px;
}
.logo { display: flex; align-items: center; gap: 12px; }
.logo-icon { width: 36px; height: 36px; }
.logo h1 { font-size: 1.15rem; font-weight: 700; letter-spacing: -0.02em; }
.logo .accent {
    background: linear-gradient(135deg, var(--accent-indigo), var(--accent-pink));
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
    background-clip: text;
}
nav { display: flex; gap: 8px; }
.nav-btn {
    display: flex; align-items: center; gap: 6px;
    padding: 8px 14px; border-radius: var(--radius-sm);
    border: 1px solid var(--glass-border); background: var(--glass-bg);
    color: var(--text-secondary); font-size: 0.8rem; font-weight: 500;
    cursor: pointer; transition: var(--transition);
    font-family: inherit;
}
.nav-btn:hover { background: rgba(255,255,255,0.08); color: var(--text-primary); }
.nav-btn.danger:hover { border-color: var(--danger); color: var(--danger); }

/* ===== Main Layout ===== */
#app-main {
    position: relative; z-index: 1;
    display: grid;
    grid-template-columns: 280px 1fr 300px;
    gap: 16px;
    max-width: 1600px; margin: 0 auto;
    padding: 16px 24px;
    min-height: calc(100vh - 100px);
}

/* ===== Panels ===== */
.panel {
    border-radius: var(--radius-lg);
    padding: 20px;
    display: flex; flex-direction: column; gap: 16px;
    overflow-y: auto; max-height: calc(100vh - 100px);
    position: sticky; top: 76px;
    scrollbar-width: thin;
    scrollbar-color: rgba(255,255,255,0.1) transparent;
}
.panel::-webkit-scrollbar { width: 4px; }
.panel::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.1); border-radius: 2px; }

.panel-header {
    display: flex; align-items: center; justify-content: space-between;
    padding-bottom: 12px; border-bottom: 1px solid var(--glass-border);
}
.panel-header h2 { font-size: 0.95rem; font-weight: 700; letter-spacing: -0.01em; }

.badge {
    font-size: 0.65rem; font-weight: 600; text-transform: uppercase;
    padding: 3px 8px; border-radius: 20px; letter-spacing: 0.05em;
    background: rgba(99, 102, 241, 0.15); color: var(--accent-indigo);
}
.badge.untrained { background: rgba(255,255,255,0.06); color: var(--text-muted); }
.badge.trained { background: rgba(52, 211, 153, 0.15); color: var(--accent-green); }

/* ===== Control Sections ===== */
.control-section { display: flex; flex-direction: column; gap: 8px; }
.control-label {
    font-size: 0.75rem; font-weight: 600; text-transform: uppercase;
    letter-spacing: 0.06em; color: var(--text-muted);
    display: flex; justify-content: space-between; align-items: center;
}
.control-value { color: var(--accent-indigo); text-transform: none; }

/* Class Selector */
.class-selector { display: flex; flex-direction: column; gap: 4px; }
.class-btn {
    display: flex; align-items: center; gap: 8px;
    padding: 8px 12px; border-radius: var(--radius-sm);
    border: 1px solid transparent; background: rgba(255,255,255,0.03);
    color: var(--text-secondary); font-size: 0.82rem; font-weight: 500;
    cursor: pointer; transition: var(--transition); font-family: inherit;
}
.class-btn:hover { background: rgba(255,255,255,0.06); }
.class-btn.active {
    border-color: var(--class-color);
    background: color-mix(in srgb, var(--class-color) 12%, transparent);
    color: var(--text-primary);
    box-shadow: 0 0 12px color-mix(in srgb, var(--class-color) 20%, transparent);
}
.class-dot {
    width: 10px; height: 10px; border-radius: 50%;
    background: var(--class-color);
}
.counter-dot {
    width: 8px; height: 8px; border-radius: 50%;
    background: var(--class-color);
}

/* Dataset Buttons */
.dataset-btns { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; }
.ds-btn {
    display: flex; align-items: center; justify-content: center; gap: 6px;
    padding: 8px; border-radius: var(--radius-sm);
    border: 1px solid var(--glass-border); background: var(--glass-bg);
    color: var(--text-secondary); font-size: 0.75rem; font-weight: 500;
    cursor: pointer; transition: var(--transition); font-family: inherit;
}
.ds-btn:hover {
    background: rgba(99, 102, 241, 0.1); border-color: var(--accent-indigo);
    color: var(--text-primary);
}

/* Toggles */
.toggle-group { display: flex; flex-direction: column; gap: 6px; }
.toggle {
    display: flex; align-items: center; gap: 10px;
    cursor: pointer; font-size: 0.8rem; color: var(--text-secondary);
    padding: 4px 0;
}
.toggle input { display: none; }
.toggle-slider {
    width: 34px; height: 18px; border-radius: 10px;
    background: rgba(255,255,255,0.1); position: relative;
    transition: var(--transition); flex-shrink: 0;
}
.toggle-slider::after {
    content: ''; position: absolute; top: 2px; left: 2px;
    width: 14px; height: 14px; border-radius: 50%;
    background: var(--text-muted); transition: var(--transition);
}
.toggle input:checked + .toggle-slider {
    background: var(--accent-indigo);
}
.toggle input:checked + .toggle-slider::after {
    transform: translateX(16px); background: white;
}

/* Range Slider */
.styled-range {
    -webkit-appearance: none; appearance: none;
    width: 100%; height: 4px; border-radius: 2px;
    background: rgba(255,255,255,0.1); outline: none;
    cursor: pointer;
}
.styled-range::-webkit-slider-thumb {
    -webkit-appearance: none; appearance: none;
    width: 16px; height: 16px; border-radius: 50%;
    background: var(--accent-indigo); border: 2px solid white;
    cursor: pointer; box-shadow: 0 0 8px var(--accent-indigo-glow);
}

/* Action Buttons */
.action-buttons { display: flex; flex-direction: column; gap: 6px; margin-top: 4px; }
.action-btn {
    display: flex; align-items: center; justify-content: center; gap: 8px;
    padding: 10px 16px; border-radius: var(--radius-sm);
    font-size: 0.82rem; font-weight: 600; cursor: pointer;
    transition: var(--transition); border: none; font-family: inherit;
}
.action-btn.primary {
    background: linear-gradient(135deg, var(--accent-indigo), #818cf8);
    color: white;
    box-shadow: 0 4px 15px var(--accent-indigo-glow);
}
.action-btn.primary:hover:not(:disabled) { transform: translateY(-1px); box-shadow: 0 6px 20px var(--accent-indigo-glow); }
.action-btn.primary:disabled { opacity: 0.4; cursor: not-allowed; }
.action-btn.secondary {
    background: rgba(255,255,255,0.05); color: var(--text-secondary);
    border: 1px solid var(--glass-border);
}
.action-btn.secondary:hover { background: rgba(255,255,255,0.08); color: var(--text-primary); }

/* Point Counter */
.point-counter {
    display: flex; flex-direction: column; gap: 4px;
    padding: 10px 12px; border-radius: var(--radius-sm);
    background: rgba(255,255,255,0.02); border: 1px solid var(--glass-border);
}
.counter-item {
    display: flex; align-items: center; gap: 8px;
    font-size: 0.78rem; color: var(--text-secondary);
}
.counter-item strong { margin-left: auto; color: var(--text-primary); font-variant-numeric: tabular-nums; }

/* ===== Canvas ===== */
.canvas-container { display: flex; flex-direction: column; gap: 12px; min-width: 0; }
.canvas-wrapper {
    position: relative; border-radius: var(--radius-lg); overflow: hidden;
    aspect-ratio: 1 / 1; max-height: calc(100vh - 180px);
}
#main-canvas { width: 100%; height: 100%; cursor: crosshair; display: block; }
.canvas-placeholder {
    position: absolute; inset: 0;
    display: flex; align-items: center; justify-content: center;
    pointer-events: none;
}
.placeholder-content { text-align: center; color: var(--text-muted); }
.placeholder-content p { font-size: 0.9rem; margin-top: 12px; }
.placeholder-content span { font-size: 0.75rem; opacity: 0.6; }
.canvas-placeholder.hidden { display: none; }

/* Canvas Tooltip */
.canvas-tooltip {
    position: absolute; pointer-events: none;
    padding: 6px 10px; border-radius: var(--radius-sm);
    background: rgba(10,10,26,0.9); border: 1px solid var(--glass-border);
    font-size: 0.72rem; color: var(--text-primary);
    font-family: 'JetBrains Mono', monospace;
    white-space: nowrap; z-index: 10;
}
.canvas-tooltip.hidden { display: none; }

/* Hover Probability Bars */
.hover-probs {
    border-radius: var(--radius-md); padding: 14px 16px;
}
.hover-probs.hidden { display: none; }
.hover-probs-title { font-size: 0.7rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.06em; color: var(--text-muted); margin-bottom: 10px; }
.prob-bars { display: flex; flex-direction: column; gap: 8px; }
.prob-bar-row { display: flex; align-items: center; gap: 8px; }
.prob-label { font-size: 0.75rem; font-weight: 700; color: var(--class-color); width: 14px; text-align: center; }
.prob-bar-track { flex: 1; height: 8px; border-radius: 4px; background: rgba(255,255,255,0.06); overflow: hidden; }
.prob-bar-fill { height: 100%; border-radius: 4px; background: var(--class-color); transition: width 0.15s ease; width: 0%; }
.prob-value { font-size: 0.72rem; font-family: 'JetBrains Mono', monospace; color: var(--text-secondary); width: 38px; text-align: right; }
.hover-prediction { margin-top: 8px; font-size: 0.78rem; color: var(--text-secondary); text-align: center; padding-top: 8px; border-top: 1px solid var(--glass-border); }
.hover-prediction strong { color: var(--text-primary); }

/* ===== Stats Panel ===== */
.stats-section { display: flex; flex-direction: column; gap: 8px; }
.stats-title { font-size: 0.75rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.06em; color: var(--text-muted); }
.empty-state { font-size: 0.78rem; color: var(--text-muted); font-style: italic; padding: 12px; text-align: center; background: rgba(255,255,255,0.02); border-radius: var(--radius-sm); }

/* Priors */
.priors-container { display: flex; flex-direction: column; gap: 6px; }
.prior-row {
    display: flex; align-items: center; gap: 8px;
    padding: 8px 10px; border-radius: var(--radius-sm);
    background: rgba(255,255,255,0.02); border: 1px solid var(--glass-border);
}
.prior-row .prior-dot { width: 8px; height: 8px; border-radius: 50%; }
.prior-row .prior-name { font-size: 0.8rem; color: var(--text-secondary); }
.prior-row .prior-val { margin-left: auto; font-size: 0.82rem; font-weight: 600; font-family: 'JetBrains Mono', monospace; color: var(--text-primary); }

/* Feature Tabs */
.feature-tabs { display: flex; gap: 4px; }
.feat-tab {
    flex: 1; padding: 6px; border-radius: var(--radius-sm);
    border: 1px solid var(--glass-border); background: transparent;
    color: var(--text-muted); font-size: 0.72rem; font-weight: 600;
    cursor: pointer; transition: var(--transition); font-family: inherit;
}
.feat-tab.active { background: rgba(99,102,241,0.12); border-color: var(--accent-indigo); color: var(--accent-indigo); }

/* Gaussian Params Table */
.gaussian-params { display: flex; flex-direction: column; gap: 4px; }
.param-row {
    display: grid; grid-template-columns: 20px 1fr 1fr; gap: 8px; align-items: center;
    padding: 6px 10px; border-radius: var(--radius-sm);
    background: rgba(255,255,255,0.02); font-size: 0.78rem;
}
.param-row .param-dot { width: 8px; height: 8px; border-radius: 50%; }
.param-row span { font-family: 'JetBrains Mono', monospace; color: var(--text-secondary); }
.param-row .param-label { font-size: 0.65rem; color: var(--text-muted); }

/* Curve Canvas */
.curve-canvas-wrapper {
    border-radius: var(--radius-sm); overflow: hidden;
    background: rgba(0,0,0,0.2); border: 1px solid var(--glass-border);
    height: 140px;
}
#curve-canvas { width: 100%; height: 100%; display: block; }

/* Formula */
.formula-card {
    padding: 16px; border-radius: var(--radius-md); text-align: center;
}
.formula { font-size: 1.05rem; margin-bottom: 12px; color: var(--text-primary); }
.frac { display: inline-flex; flex-direction: column; align-items: center; vertical-align: middle; margin: 0 4px; }
.num { border-bottom: 1px solid var(--text-muted); padding-bottom: 2px; }
.den { padding-top: 2px; }
.formula-legend { display: flex; flex-wrap: wrap; gap: 6px 12px; justify-content: center; }
.formula-legend span { font-size: 0.68rem; color: var(--text-muted); }
.formula-legend em { color: var(--accent-indigo); font-style: normal; }

/* Accuracy */
.accuracy-display { display: flex; justify-content: center; padding: 10px; }
.accuracy-ring { position: relative; width: 100px; height: 100px; display: flex; align-items: center; justify-content: center; }
.accuracy-ring svg { position: absolute; inset: 0; transform: rotate(-90deg); }
.ring-bg { fill: none; stroke: rgba(255,255,255,0.06); stroke-width: 8; }
.ring-fill {
    fill: none; stroke: var(--accent-green); stroke-width: 8;
    stroke-linecap: round; stroke-dasharray: 326.7; stroke-dashoffset: 326.7;
    transition: stroke-dashoffset 1s ease;
}
.accuracy-value { font-size: 1.3rem; font-weight: 800; font-family: 'JetBrains Mono', monospace; }

/* ===== Modal ===== */
.modal-overlay {
    position: fixed; inset: 0; z-index: 1000;
    background: rgba(0,0,0,0.7); backdrop-filter: blur(8px);
    display: flex; align-items: center; justify-content: center;
    padding: 24px; animation: fadeIn 0.25s ease;
}
.modal-overlay.hidden { display: none; }
.modal {
    background: var(--bg-secondary); border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl); max-width: 520px; width: 100%;
    padding: 32px; position: relative;
    animation: slideUp 0.35s cubic-bezier(0.16, 1, 0.3, 1);
}
.modal-close {
    position: absolute; top: 16px; right: 16px;
    background: none; border: none; color: var(--text-muted);
    font-size: 1.4rem; cursor: pointer; transition: var(--transition);
    width: 32px; height: 32px; display: flex; align-items: center; justify-content: center;
    border-radius: 50%;
}
.modal-close:hover { background: rgba(255,255,255,0.08); color: var(--text-primary); }

.tutorial-slide { display: none; text-align: center; padding: 16px 0; }
.tutorial-slide.active { display: block; animation: fadeIn 0.3s ease; }
.slide-icon { font-size: 2.5rem; margin-bottom: 16px; }
.tutorial-slide h2 { font-size: 1.15rem; font-weight: 700; margin-bottom: 10px; }
.tutorial-slide p { font-size: 0.88rem; color: var(--text-secondary); line-height: 1.7; }

.tutorial-nav { display: flex; align-items: center; justify-content: space-between; margin-top: 20px; }
.tut-btn {
    padding: 8px 16px; border-radius: var(--radius-sm);
    border: 1px solid var(--glass-border); background: var(--glass-bg);
    color: var(--text-secondary); font-size: 0.8rem; cursor: pointer;
    transition: var(--transition); font-family: inherit;
}
.tut-btn:hover:not(:disabled) { background: rgba(255,255,255,0.08); color: var(--text-primary); }
.tut-btn:disabled { opacity: 0.3; cursor: not-allowed; }
.tutorial-dots { display: flex; gap: 6px; }
.dot {
    width: 8px; height: 8px; border-radius: 50%;
    background: rgba(255,255,255,0.15); transition: var(--transition); cursor: pointer;
}
.dot.active { background: var(--accent-indigo); }

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

/* ===== Footer ===== */
#main-footer {
    position: relative; z-index: 1;
    text-align: center; padding: 16px;
    font-size: 0.72rem; color: var(--text-muted);
    border-top: 1px solid var(--glass-border);
}

/* ===== Responsive ===== */
@media (max-width: 1100px) {
    #app-main { grid-template-columns: 1fr; }
    .panel { position: static; max-height: none; }
    .canvas-wrapper { aspect-ratio: 4/3; }
}