:root {
    /* カラーパレット */
    --bg-color: #050814;
    --panel-bg: rgba(13, 19, 38, 0.7);
    --panel-bg-solid: rgba(13, 19, 38, 0.95);
    --border-color: rgba(56, 189, 248, 0.25);
    --border-hover: rgba(56, 189, 248, 0.6);
    --text-color: #f1f5f9;
    --text-muted: #94a3b8;
    --accent-ground: #38bdf8;
    --accent-space: #a855f7;
    --accent-moon: #fbbf24;
    --glow-ground: rgba(56, 189, 248, 0.3);
    --glow-space: rgba(168, 85, 247, 0.3);

    /* タイポグラフィ */
    --font-family: 'Noto Sans JP', sans-serif;
    --font-display: 'Orbitron', sans-serif;

    /* トランジション */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* リセット */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-color);
    background-image:
        radial-gradient(at 15% 15%, rgba(56, 189, 248, 0.12) 0px, transparent 50%),
        radial-gradient(at 85% 85%, rgba(168, 85, 247, 0.12) 0px, transparent 50%),
        linear-gradient(180deg, #030611 0%, #080d21 100%);
    color: var(--text-color);
    font-family: var(--font-family);
    min-height: 100vh;
    overflow-x: hidden;
}

.app-container {
    max-width: 1300px;
    margin: 0 auto;
    padding: 20px 24px 40px;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* ヘッダー */
header {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    margin-bottom: 20px;
    position: relative;
}

.header-left {
    justify-self: start;
}

.header-right {
    justify-self: end;
}

.back-link {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.85rem;
    padding: 8px 14px;
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all var(--transition-fast);
}

.back-link:hover {
    color: #ffffff;
    background: rgba(56, 189, 248, 0.15);
    border-color: var(--accent-ground);
}

.header-center {
    text-align: center;
}

h1 {
    font-family: var(--font-display);
    font-size: clamp(1.4rem, 4vw, 2.2rem);
    font-weight: 800;
    letter-spacing: 2px;
    background: linear-gradient(90deg, #ffffff, #7dd3fc, #c084fc);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    filter: drop-shadow(0 0 16px rgba(56, 189, 248, 0.3));
}

.subtitle {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-top: 4px;
    letter-spacing: 0.5px;
}

/* メインレイアウト */
.main-layout {
    display: flex;
    flex-direction: column;
    gap: 20px;
    flex: 1;
}

/* 2画面 3D ビューポート */
.dual-viewport-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    width: 100%;
}

.viewport-box {
    background: var(--panel-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.5);
    position: relative;
    transition: border-color var(--transition-normal);
}

.viewport-box:hover {
    border-color: var(--border-hover);
}

.viewport-header {
    padding: 10px 16px;
    background: rgba(0, 0, 0, 0.35);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: 0.82rem;
}

.view-tag {
    font-weight: 700;
    padding: 4px 10px;
    border-radius: 6px;
    font-size: 0.8rem;
    letter-spacing: 0.5px;
}

.ground-tag {
    background: rgba(56, 189, 248, 0.15);
    color: var(--accent-ground);
    border: 1px solid rgba(56, 189, 248, 0.3);
}

.space-tag {
    background: rgba(168, 85, 247, 0.15);
    color: var(--accent-space);
    border: 1px solid rgba(168, 85, 247, 0.3);
}

.direction-indicator,
.sun-indicator {
    color: var(--text-muted);
    font-size: 0.78rem;
    display: flex;
    gap: 10px;
}

.canvas-wrapper {
    position: relative;
    width: 100%;
    aspect-ratio: 4 / 3;
    background: #000;
    overflow: hidden;
}

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

/* 地上ビュー 方角ラベル */
.compass-label {
    position: absolute;
    bottom: 8px;
    font-size: 0.75rem;
    font-weight: 700;
    padding: 3px 8px;
    border-radius: 4px;
    background: rgba(0, 0, 0, 0.6);
    color: #e2e8f0;
    border: 1px solid rgba(255, 255, 255, 0.15);
    pointer-events: none;
    user-select: none;
}

.compass-east {
    left: 10px;
    color: #93c5fd;
}

.compass-south {
    left: 50%;
    transform: translateX(-50%);
    color: #fde047;
}

.compass-west {
    right: 10px;
    color: #fca5a5;
}

/* 宇宙ビュー HUD */
.space-hud {
    position: absolute;
    top: 10px;
    right: 10px;
    pointer-events: none;
}

.sun-dir-label {
    background: rgba(251, 191, 36, 0.15);
    color: #fbbf24;
    border: 1px solid rgba(251, 191, 36, 0.4);
    padding: 4px 10px;
    border-radius: 6px;
    font-size: 0.75rem;
    font-weight: 600;
}

/* コントロールセクション */
.controls-section {
    width: 100%;
}

.slider-control-card {
    background: var(--panel-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 20px 24px;
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.4);
    display: flex;
    flex-direction: column;
    gap: 16px;
}

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

.slider-title {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-color);
    letter-spacing: 0.5px;
}

.phase-display-badge {
    font-family: var(--font-display), var(--font-family);
    background: rgba(251, 191, 36, 0.15);
    border: 1px solid rgba(251, 191, 36, 0.4);
    color: #fbbf24;
    padding: 4px 14px;
    border-radius: 20px;
    font-size: 0.95rem;
    font-weight: 700;
    box-shadow: 0 0 12px rgba(251, 191, 36, 0.2);
}

/* スライダー本体 */
.slider-wrapper {
    position: relative;
    width: 100%;
    padding: 10px 0 24px;
}

input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 10px;
    background: linear-gradient(90deg, #60a5fa 0%, #a855f7 50%, #f43f5e 100%);
    border-radius: 5px;
    outline: none;
    cursor: pointer;
    box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.6);
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 26px;
    height: 26px;
    border-radius: 50%;
    background: #ffffff;
    border: 3px solid #00f0ff;
    box-shadow: 0 0 15px #00f0ff, 0 2px 6px rgba(0, 0, 0, 0.5);
    cursor: grab;
    transition: transform var(--transition-fast), background var(--transition-fast);
}

input[type="range"]:active::-webkit-slider-thumb {
    cursor: grabbing;
    transform: scale(1.15);
    background: #e0f2fe;
}

input[type="range"]::-moz-range-thumb {
    width: 26px;
    height: 26px;
    border-radius: 50%;
    background: #ffffff;
    border: 3px solid #00f0ff;
    box-shadow: 0 0 15px #00f0ff, 0 2px 6px rgba(0, 0, 0, 0.5);
    cursor: grab;
}

.slider-ticks {
    display: flex;
    justify-content: space-between;
    margin-top: 8px;
    font-size: 0.75rem;
    color: var(--text-muted);
    user-select: none;
}

.tick {
    cursor: pointer;
    transition: color var(--transition-fast);
}

.tick:hover {
    color: var(--text-color);
}

/* クイックボタン */
.quick-buttons-wrapper {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.quick-btn {
    flex: 1;
    min-width: 140px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.12);
    color: var(--text-color);
    padding: 10px 12px;
    border-radius: 10px;
    font-size: 0.85rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    transition: all var(--transition-normal);
}

.quick-btn:hover {
    background: rgba(56, 189, 248, 0.12);
    border-color: rgba(56, 189, 248, 0.4);
    transform: translateY(-2px);
}

.quick-btn.active {
    background: linear-gradient(135deg, rgba(56, 189, 248, 0.25), rgba(168, 85, 247, 0.25));
    border-color: var(--accent-ground);
    color: #ffffff;
    box-shadow: 0 0 16px rgba(56, 189, 248, 0.25);
    font-weight: 700;
}

/* 解説セクション */
.info-section {
    width: 100%;
}

.info-card {
    background: var(--panel-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 24px;
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.4);
}

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

.info-col {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.col-title {
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: 0.5px;
    padding-bottom: 6px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.ground-color {
    color: var(--accent-ground);
}

.space-color {
    color: #d8b4fe;
}

.info-text-box {
    font-size: 0.9rem;
    line-height: 1.7;
    color: var(--text-color);
    background: rgba(0, 0, 0, 0.25);
    padding: 16px;
    border-radius: 10px;
    border: 1px solid rgba(255, 255, 255, 0.05);
    min-height: 110px;
}

.info-text-box strong {
    color: #38bdf8;
}

.info-col:last-child .info-text-box strong {
    color: #c084fc;
}

/* レスポンシブ (タブレット・スマホ) */
@media (max-width: 1024px) {
    .app-container {
        padding: 12px 16px 24px;
    }

    header {
        margin-bottom: 12px;
    }

    .main-layout {
        display: flex;
        flex-direction: column;
        gap: 12px;
    }

    /* ビューポートコンテナの階層を解除し、各子要素の並び順を制御 */
    .dual-viewport-container {
        display: contents;
    }

    /* ① 地上視点ビュー */
    .ground-box {
        order: 1;
        width: 100%;
    }

    /* ② 操作コントロールエリア（2画面の中間に配置） */
    .controls-section {
        order: 2;
        width: 100%;
    }

    .slider-control-card {
        padding: 12px 18px;
        gap: 8px;
    }

    .slider-wrapper {
        padding: 4px 0 16px;
    }

    .quick-buttons-wrapper {
        gap: 6px;
    }

    .quick-btn {
        padding: 7px 10px;
        font-size: 0.8rem;
        min-width: 110px;
    }

    /* ③ 宇宙俯瞰ビュー */
    .space-box {
        order: 3;
        width: 100%;
    }

    /* ④ 解説パネル */
    .info-section {
        order: 4;
        width: 100%;
    }

    .info-card {
        padding: 16px;
    }

    .canvas-wrapper {
        aspect-ratio: 16 / 7.5;
    }
}

@media (max-width: 860px) {
    .app-container {
        padding: 10px 10px 24px;
    }

    header {
        display: flex;
        flex-direction: column;
        gap: 8px;
    }

    .header-left {
        align-self: flex-start;
    }

    .info-grid {
        grid-template-columns: 1fr;
        gap: 12px;
    }

    .quick-buttons-wrapper {
        display: grid;
        grid-template-columns: 1fr 1fr;
    }

    .quick-btn:last-child {
        grid-column: 1 / -1;
    }
}