/**
 * Nook Audio Lounge - Material Design 3 Adaptive Navigation
 * YouTube 2025-2026 UI Architecture
 * * 構成:
 * - M3 デザインシステム（ダークテーマ最適化）
 * - 3段階モード（Rail / Expanded / Overlay）
 * - ホバー自動展開ロジック
 * - 通知・進捗トラッカー用スタイル
 * * @version 2.0.0
 * @author Nook Development Team
 */

/* ========================================
   CSS Custom Properties (M3 Design Tokens)
   ======================================== */
:root {
    /* Nook Chic Color Palette */
    --md-sys-color-primary: #D4AF37;           /* Champagne Gold */
    --md-sys-color-on-primary: #0F1219;        /* Deep Midnight */
    --md-sys-color-primary-container: rgba(212, 175, 55, 0.15);
    --md-sys-color-on-primary-container: #D4AF37;
    
    --md-sys-color-surface: #0F1219;
    --md-sys-color-on-surface: #CBD5E1;        /* Main Text */
    --md-sys-color-surface-variant: rgba(255, 255, 255, 0.05);
    --md-sys-color-on-surface-variant: #94A3B8; /* Sub Text */
    
    --md-sys-color-outline-variant: rgba(212, 175, 55, 0.1);
    --md-sys-color-success: #4ADE80;
    --md-sys-color-error: #F87171;
    
    /* Dimensions */
    --nav-width-rail: 50px;
    --nav-width-expanded: 256px;
    --nav-transition-duration: 300ms;
    --nav-transition-easing: cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Layering */
    --z-index-nav: 1000;
    --z-index-toggle: 1001;
    --z-index-overlay: 999;
}

/* ========================================
   Base Navigation Container
   ======================================== */
.audio-nav {
    position: fixed;
    top: 0;
    left: 0;
    height: 100vh;
    background-color: var(--md-sys-color-surface);
    border-right: 1px solid var(--md-sys-color-outline-variant);
    transition: width var(--nav-transition-duration) var(--nav-transition-easing),
                transform var(--nav-transition-duration) var(--nav-transition-easing),
                box-shadow var(--nav-transition-duration);
    overflow-x: hidden;
    overflow-y: auto;
    z-index: var(--z-index-nav);
    width: var(--nav-width-rail); /* 初期状態 */
}

/* スクロールバーのカスタマイズ */
.audio-nav::-webkit-scrollbar { width: 4px; }
.audio-nav::-webkit-scrollbar-track { background: transparent; }
.audio-nav::-webkit-scrollbar-thumb { background: rgba(212, 175, 55, 0.2); border-radius: 2px; }

/* ========================================
   Display Modes (JS連携)
   ======================================== */

/* Rail Mode */
.audio-nav.rail { width: var(--nav-width-rail); }

/* Expanded / Pinned Mode */
.audio-nav.expanded, 
.audio-nav.nav-pinned { 
    width: var(--nav-width-expanded); 
}

/* Desktop Hover Expansion */
@media (min-width: 769px) {
    .audio-nav:hover:not(.overlay) {
        width: var(--nav-width-expanded);
        box-shadow: 10px 0 40px rgba(0, 0, 0, 0.6);
    }
}

/* Overlay Mode (Mobile) */
.audio-nav.overlay {
    width: var(--nav-width-expanded);
    transform: translateX(-100%);
}

.audio-nav.overlay.open {
    transform: translateX(0);
    box-shadow: 20px 0 50px rgba(0, 0, 0, 0.8);
}

/* ========================================
   Display Elements Control
   ======================================== */

/* テキストとロゴテキストの初期非表示（Rail時） */
.nav-text, .audio-nav-logo-text {
    opacity: 0;
    width: 0;
    display: inline-block;
    white-space: nowrap;
    overflow: hidden;
    transition: opacity 0.2s, width 0.2s, margin 0.2s;
    margin-left: 0;
    vertical-align: middle;
}

/* 展開時（ホバー or 固定クラス）に表示 */
.audio-nav:hover .nav-text,
.audio-nav.expanded .nav-text,
.audio-nav.nav-pinned .nav-text,
.audio-nav.open .nav-text,
.audio-nav:hover .audio-nav-logo-text,
.audio-nav.expanded .audio-nav-logo-text,
.audio-nav.nav-pinned .audio-nav-logo-text,
.audio-nav.open .audio-nav-logo-text {
    opacity: 1;
    width: auto;
    margin-left: 12px;
}

/* ========================================
   Navigation Header
   ======================================== */
.audio-nav-header {
    display: flex;
    align-items: center;
    padding: 16px 12px;
    min-height: 64px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.audio-nav-logo {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: var(--md-sys-color-primary);
}

.audio-nav-logo-icon {
    font-size: 32px;
    width: 48px;
    text-align: center;
}

/* ========================================
   Navigation Items (M3 Style)
   ======================================== */
.audio-nav-section { padding: 12px 0; }

.audio-nav-item {
    display: flex;
    align-items: center;
    padding: 12px;
    margin: 4px 8px;
    border-radius: 28px;
    text-decoration: none;
    color: var(--md-sys-color-on-surface);
    transition: all 0.2s var(--nav-transition-easing);
    position: relative;
    justify-content: center; /* Rail時は中央 */
}

/* 展開時のアイテム配置調整 */
.audio-nav:hover .audio-nav-item,
.audio-nav.expanded .audio-nav-item,
.audio-nav.nav-pinned .audio-nav-item,
.audio-nav.open .audio-nav-item {
    justify-content: flex-start;
    padding-left: 16px;
}

.audio-nav-item:hover {
    background-color: var(--md-sys-color-surface-variant);
}

.audio-nav-item.active {
    background-color: var(--md-sys-color-primary-container);
    color: var(--md-sys-color-on-primary-container);
}

.nav-icon {
    font-size: 24px;
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

/* ========================================
   Progress & Analytics Features (STEP 3/4)
   ======================================== */

/* 進捗バー */
.progress-indicator {
    position: absolute;
    bottom: 4px;
    left: 16px;
    right: 16px;
    height: 2px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 1px;
    overflow: hidden;
    opacity: 0;
    transition: opacity 0.3s;
}

.audio-nav:hover .progress-indicator,
.audio-nav.expanded .progress-indicator { opacity: 1; }

.progress-indicator::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    width: var(--progress, 0%);
    background: var(--md-sys-color-primary);
    transition: width 0.4s ease;
}

/* 完了マーク */
.audio-nav-item.completed::after {
    content: '✓';
    position: absolute;
    right: 12px;
    font-size: 10px;
    color: var(--md-sys-color-success);
}

/* 人気バッジ */
.badge.popular {
    margin-left: auto;
    font-size: 12px;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); opacity: 0.8; }
    50% { transform: scale(1.2); opacity: 1; }
}

/* ========================================
   Toggle Button
   ======================================== */
.nav-toggle {
    position: fixed;
    top: 16px;
    left: 12px; /* Rail幅に収まる位置 */
    width: 48px;
    height: 48px;
    background: var(--md-sys-color-primary);
    border: none;
    border-radius: 50%;
    color: var(--md-sys-color-on-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: var(--z-index-toggle);
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
    transition: all var(--nav-transition-duration) var(--nav-transition-easing);
}

.nav-toggle:hover {
    transform: scale(1.05);
    background: #E5C158; /* Lighter Gold */
}

/* ナビ展開時のボタンスライド移動 */
.audio-nav:hover + .nav-toggle,
.audio-nav.expanded + .nav-toggle,
.audio-nav.nav-pinned + .nav-toggle {
    left: calc(var(--nav-width-expanded) - 24px);
}

/* ========================================
   Overlay Scrim (Mobile)
   ======================================== */
.audio-nav-overlay-scrim {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    z-index: var(--z-index-overlay);
}

.audio-nav-overlay-scrim.visible {
    opacity: 1;
    visibility: visible;
}

/* ========================================
   Notifications
   ======================================== */
.audio-nav-notification {
    position: fixed;
    bottom: 32px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--md-sys-color-primary);
    color: var(--md-sys-color-on-primary);
    padding: 12px 24px;
    border-radius: 30px;
    font-size: 14px;
    font-weight: 600;
    z-index: 10000;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
    animation: slideUp 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes slideUp {
    from { transform: translateX(-50%) translateY(40px); opacity: 0; }
    to { transform: translateX(-50%) translateY(0); opacity: 1; }
}

/* ========================================
   Content Offset (Main Content)
   ======================================== */
.nav-mode-rail .audio-nav-active { margin-left: var(--nav-width-rail); }
.nav-mode-expanded .audio-nav-active { margin-left: var(--nav-width-expanded); }
.nav-mode-overlay .audio-nav-active { margin-left: 0; }

@media (max-width: 768px) {
    .audio-nav-active { margin-left: 0 !important; }
}

/* Cocoonテーマ等の他要素との干渉防止 */
.audio-nav-active {
    transition: margin-left var(--nav-transition-duration) var(--nav-transition-easing);
}