:root {
    --bg-app: #f4f4f4;
    --bg-panel: #ffffff;
    --bg-elevated: #e8e8e8;
    --bg-canvas: #fafafa;
    --text-main: #1a1a1a;
    --text-muted: #555;
    --text-inverse: #ffffff;
    --accent: #1f6feb;
    --border: #cbd5e1;
    --header-bg: rgba(0, 0, 0, 0.04);
    --control-bg: rgba(0, 0, 0, 0.03);
    --btn-primary: #16a34a;
    --btn-primary-hover: #22c55e;
    --btn-secondary: #94a3b8;
    --btn-secondary-hover: #cbd5e1;
    --btn-accent: #1f6feb;
    --hr-color: rgba(0, 0, 0, 0.1);
    --canvas-bg: #fafafa;
    --canvas-grid: rgba(0, 0, 0, 0.12);
    --canvas-axis: #555;
    --canvas-label: #555;
    --proximity-alert-bg: rgba(200, 50, 50, 0.95);
    --alert-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);

    /* Sémantiques (conservées sur les 2 thèmes) */
    --yellow-io: #ffcc00;
    --white-europa: #ffffff;
    --grey-ganymede: #a0a0a0;
    --brown-callisto: #d4a373;
    --jupiter-1: #d8ca9d;
    --jupiter-2: #a08f70;
    --jupiter-3: #e3dcca;
    --jupiter-4: #cfc2a0;
    --jupiter-5: #8c7a56;
    --jupiter-shadow: rgba(0, 0, 0, 0.3);
    --earth-color: #1f6feb;
    --measure-gold: #d29922;
    --measure-cyan: #06b6d4;
    --highlight-gold: rgba(255, 215, 0, 0.1);
    --highlight-cyan: rgba(6, 182, 212, 0.1);
    --beta-green: #16a34a;
    --beta-red: #dc2626;
    --moon-orbit: rgba(0, 0, 0, 0.15);
    --graph-axis: rgba(0, 0, 0, 0.2);
    --graph-label: #555;
}

:root[data-theme="dark"] {
    --bg-app: #0f1115;
    --bg-panel: #161b22;
    --bg-elevated: #21262d;
    --bg-canvas: #0a0e14;
    --text-main: #c9d1d9;
    --text-muted: #8b949e;
    --text-inverse: #0f1115;
    --accent: #58a6ff;
    --border: #30363d;
    --header-bg: rgba(255, 255, 255, 0.05);
    --control-bg: rgba(255, 255, 255, 0.03);
    --btn-primary: #238636;
    --btn-primary-hover: #2ea043;
    --btn-secondary: #30363d;
    --btn-secondary-hover: #424a53;
    --btn-accent: #58a6ff;
    --hr-color: rgba(255, 255, 255, 0.1);
    --canvas-bg: #000;
    --canvas-grid: rgba(255, 255, 255, 0.1);
    --canvas-axis: rgba(255, 255, 255, 0.2);
    --canvas-label: #8b949e;
    --proximity-alert-bg: rgba(200, 50, 50, 0.9);
    --alert-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);

    --yellow-io: #ffcc00;
    --white-europa: #ffffff;
    --grey-ganymede: #a0a0a0;
    --brown-callisto: #d4a373;
    --jupiter-1: #d8ca9d;
    --jupiter-2: #a08f70;
    --jupiter-3: #e3dcca;
    --jupiter-4: #cfc2a0;
    --jupiter-5: #8c7a56;
    --jupiter-shadow: rgba(0, 0, 0, 0.5);
    --earth-color: #58a6ff;
    --measure-gold: #FFD700;
    --measure-cyan: #0ff;
    --highlight-gold: rgba(255, 215, 0, 0.1);
    --highlight-cyan: rgba(0, 255, 255, 0.1);
    --beta-green: #2ea043;
    --beta-red: #ff4444;
    --moon-orbit: rgba(255, 255, 255, 0.1);
    --graph-axis: rgba(255, 255, 255, 0.2);
    --graph-label: #8b949e;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 0;
    background-color: var(--bg-app);
    color: var(--text-main);
    font-family: 'Inter', sans-serif;
    height: 100vh;
    overflow: hidden;
    transition: background-color 0.2s ease, color 0.2s ease;
}

.app-container {
    display: grid;
    grid-template-areas:
        "header header"
        "helio earth"
        "graph controls";
    grid-template-columns: 1fr 1fr;
    grid-template-rows: auto 1fr 1fr;
    gap: 10px;
    height: 100%;
    padding: 10px;
}

.app-header {
    grid-area: header;
    background: var(--bg-panel);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 10px 16px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background-color 0.2s ease, border-color 0.2s ease;
}

.app-header h1 {
    margin: 0;
    font-size: 1.1em;
    font-weight: 600;
    color: var(--text-main);
}

.app-header .subtitle {
    color: var(--text-muted);
    font-size: 0.85em;
    font-weight: normal;
    margin-left: 10px;
}

.theme-toggle {
    background: var(--bg-elevated);
    color: var(--text-main);
    border: 1px solid var(--border);
    padding: 6px 12px;
    font-family: 'Inter', sans-serif;
    font-size: 0.8rem;
    cursor: pointer;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    border-radius: 4px;
    transition: all 0.2s;
}

.theme-toggle:hover {
    background: var(--text-main);
    color: var(--text-inverse);
}

@media (max-width: 800px) {
    .app-container {
        grid-template-areas:
            "header"
            "earth"
            "helio"
            "graph"
            "controls";
        grid-template-columns: 1fr;
        grid-template-rows: auto repeat(4, minmax(300px, 1fr));
        overflow-y: auto;
    }
}

.panel {
    background-color: var(--bg-panel);
    border: 1px solid var(--border);
    border-radius: 6px;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: background-color 0.2s ease, border-color 0.2s ease;
}

.zone-helio { grid-area: helio; }
.zone-earth { grid-area: earth; }
.zone-graph { grid-area: graph; }

.panel-header {
    background-color: var(--header-bg);
    padding: 8px 12px;
    font-size: 0.9em;
    font-weight: 600;
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
    color: var(--text-main);
}

.canvas-wrapper {
    flex: 1;
    position: relative;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at center, var(--bg-canvas) 0%, var(--canvas-bg) 100%);
    transition: background 0.2s ease;
}

canvas {
    display: block;
    width: 100%;
    height: 100%;
}

.cursor-crosshair {
    cursor: crosshair;
}

/* Controls Zone */
.zone-controls {
    padding: 16px;
    overflow-y: auto;
    gap: 20px;
}

.control-group {
    background: var(--control-bg);
    padding: 12px;
    border-radius: 4px;
    border: 1px solid var(--border);
    transition: background-color 0.2s ease, border-color 0.2s ease;
}

.control-group h3 {
    margin-top: 0;
    font-size: 1em;
    color: var(--accent);
    margin-bottom: 12px;
}

.buttons {
    display: flex;
    gap: 10px;
    margin-bottom: 10px;
}

.btn {
    padding: 8px 16px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-weight: 600;
    transition: background 0.2s;
    color: white;
}

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

.btn.primary:hover {
    background-color: var(--btn-primary-hover);
}

.btn.secondary {
    background-color: var(--btn-secondary);
    color: var(--text-main);
}

.btn.secondary:hover {
    background-color: var(--btn-secondary-hover);
}

.btn.accent {
    background-color: var(--btn-accent);
    color: var(--text-inverse);
}

input[type=range] {
    width: 100%;
    margin-top: 8px;
    accent-color: var(--accent);
}

.calc-row {
    display: flex;
    justify-content: space-between;
    margin-bottom: 5px;
    font-size: 0.9em;
}

.proximity-alert {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: var(--proximity-alert-bg);
    color: white;
    padding: 15px 25px;
    border-radius: 8px;
    font-weight: 600;
    text-align: center;
    pointer-events: none;
    box-shadow: var(--alert-shadow);
    z-index: 100;
    opacity: 0;
}

.proximity-alert.anim-active {
    animation: appearFade 3s forwards;
}

@keyframes appearFade {
    0% { opacity: 0; transform: translate(-50%, -40%); }
    10% { opacity: 1; transform: translate(-50%, -50%); }
    80% { opacity: 1; transform: translate(-50%, -50%); }
    100% { opacity: 0; transform: translate(-50%, -60%); }
}

.mono-input {
    font-family: 'Roboto Mono', monospace;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    color: var(--accent);
    width: 80px;
    text-align: right;
    padding: 2px 5px;
}

.big-result {
    display: block;
    font-size: 1.2em;
    font-weight: bold;
    color: var(--measure-gold);
    text-align: right;
    margin-top: 5px;
}

.overlay-info {
    position: absolute;
    top: 5px;
    left: 5px;
    color: var(--text-muted);
    font-size: 0.8em;
    pointer-events: none;
}