:root {
    --bg-color: #f0f4f8;
    --panel-bg: rgba(255, 255, 255, 0.85); /* グラスモーフィズム用 */
    --card-bg: #ffffff;
    --text-color: #2d3748;
    --text-secondary: #718096;
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --primary-light: #eff6ff;
    --border-color: rgba(226, 232, 240, 0.8);
    --shadow-color: rgba(148, 163, 184, 0.15);
    --shadow-hover: rgba(148, 163, 184, 0.35);
    --danger-color: #ef4444;
    --gradient-brand: linear-gradient(135deg, #3b82f6 0%, #8b5cf6 100%);
}

[data-theme="dark"] {
    --bg-color: #0f172a;
    --panel-bg: rgba(30, 41, 59, 0.85);
    --card-bg: #1e293b;
    --text-color: #f1f5f9;
    --text-secondary: #94a3b8;
    --primary-color: #60a5fa;
    --primary-hover: #3b82f6;
    --primary-light: rgba(59, 130, 246, 0.15);
    --border-color: rgba(51, 65, 85, 0.8);
    --shadow-color: rgba(0, 0, 0, 0.4);
    --shadow-hover: rgba(0, 0, 0, 0.6);
    --danger-color: #f87171;
    --gradient-brand: linear-gradient(135deg, #60a5fa 0%, #a78bfa 100%);
}

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

body {
    font-family: 'Inter', 'Helvetica Neue', Arial, 'Hiragino Kaku Gothic ProN', 'Hiragino Sans', Meiryo, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.4s ease, color 0.4s ease;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    /* 背景にうっすらとした装飾グラデーションを配置 */
    background-image: 
        radial-gradient(circle at 15% 50%, rgba(59, 130, 246, 0.05), transparent 25%),
        radial-gradient(circle at 85% 30%, rgba(139, 92, 246, 0.05), transparent 25%);
    background-attachment: fixed;
}

/* --- ヘッダー (グラスモーフィズム) --- */
header {
    background-color: var(--panel-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    padding: 0.6rem 0;
    box-shadow: 0 4px 20px var(--shadow-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

header h1 {
    font-size: 1.6rem;
    font-weight: 800;
    display: flex;
    align-items: center;
    gap: 0.6rem;
    white-space: nowrap;
    /* グラデーションテキスト */
    background: var(--gradient-brand);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -0.5px;
}

header h1 i {
    /* アイコンにもグラデーションを適用 */
    background: var(--gradient-brand);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.header-center {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.3rem;
}

.clock-display {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text-color);
    font-variant-numeric: tabular-nums;
    letter-spacing: 0.5px;
}

.visitor-counter {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--primary-color);
    background-color: var(--primary-light);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    display: flex;
    align-items: center;
    gap: 0.4rem;
    white-space: nowrap;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 1.2rem;
}

.auth-section {
    display: flex;
    align-items: center;
    gap: 0.8rem;
}

.user-name {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-color);
    background-color: var(--card-bg);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 4px var(--shadow-color);
}

.user-name.hidden {
    display: none;
}

.auth-btn {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    padding: 0.45rem 1rem;
    border-radius: 8px;
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    box-shadow: 0 2px 4px var(--shadow-color);
}

.auth-btn.hidden {
    display: none;
}

.auth-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px var(--shadow-hover);
    border-color: var(--primary-color);
}

#login-btn {
    color: #4285F4;
    border-color: rgba(66, 133, 244, 0.3);
}

#theme-toggle {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    width: 42px;
    height: 42px;
    border-radius: 12px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 2px 4px var(--shadow-color);
}

#theme-toggle:hover {
    transform: translateY(-2px) rotate(15deg);
    box-shadow: 0 4px 8px var(--shadow-hover);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

/* --- メインレイアウト --- */
.layout-wrapper {
    display: flex;
    justify-content: center;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
    padding: 1rem 0;
}

/* --- カレンダーサイドバー --- */
.calendar-sidebar {
    width: 260px;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.calendar-month {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 1.2rem;
    box-shadow: 0 4px 15px var(--shadow-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.calendar-month:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px var(--shadow-hover);
}

.calendar-title {
    text-align: center;
    font-weight: 800;
    color: var(--text-color);
    margin-bottom: 0.8rem;
    font-size: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px dashed var(--border-color);
}

.calendar-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 4px;
    text-align: center;
    font-size: 0.8rem;
}

.calendar-day-header {
    font-weight: 700;
    color: var(--text-secondary);
    padding-bottom: 0.4rem;
    font-size: 0.75rem;
}

.calendar-day-header.sun { color: var(--danger-color); }
.calendar-day-header.sat { color: var(--primary-color); }

.calendar-day {
    padding: 0.3rem 0;
    color: var(--text-primary);
    border-radius: 8px;
    transition: background-color 0.2s;
    font-weight: 500;
}

.calendar-day:hover:not(:empty) {
    background-color: var(--primary-light);
    cursor: default;
}

.calendar-day.today {
    background: var(--gradient-brand);
    color: #fff;
    font-weight: 800;
    box-shadow: 0 2px 6px rgba(59, 130, 246, 0.4);
}

.calendar-day.sun:not(.today) { color: var(--danger-color); }
.calendar-day.sat:not(.today) { color: var(--primary-color); }

/* --- メインコンテンツ（ツール一覧） --- */
main {
    flex: 1;
    max-width: 900px;
    padding: 1rem 1.5rem 3rem 1.5rem;
}

.description {
    margin-bottom: 2.5rem;
    color: var(--text-secondary);
    font-size: 1.1rem;
    text-align: center;
    font-weight: 500;
}

.site-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 1.2rem;
}

/* --- ツールカード --- */
.site-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.2rem;
    display: flex;
    flex-direction: column;
    text-decoration: none;
    color: var(--text-color);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 2px 8px var(--shadow-color);
    position: relative;
    overflow: hidden;
    min-height: 140px;
}

/* カード上部のハイライトライン */
.site-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--gradient-brand);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.site-card:hover {
    transform: translateY(-8px) scale(1.01);
    box-shadow: 0 12px 30px var(--shadow-hover);
    border-color: transparent;
}

.site-card:hover::before {
    opacity: 1;
}

.site-card.disabled {
    opacity: 0.6;
    pointer-events: none;
    filter: grayscale(100%);
}

.site-header {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    margin-bottom: 0.8rem;
}

.site-icon {
    width: 38px;
    height: 38px;
    background: var(--primary-light);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-color);
    font-size: 1.2rem;
    flex-shrink: 0;
    transition: transform 0.3s ease, background 0.3s ease, color 0.3s ease;
}

.site-card:hover .site-icon {
    background: var(--gradient-brand);
    color: #fff;
    transform: scale(1.1) rotate(-5deg);
}

.site-title {
    font-size: 1.05rem;
    font-weight: 800;
    word-break: keep-all;
    line-height: 1.2;
    letter-spacing: -0.02em;
}

.site-desc {
    color: var(--text-secondary);
    font-size: 0.85rem;
    flex: 1;
    line-height: 1.5;
}

.site-footer {
    margin-top: 1rem;
    display: flex;
    justify-content: flex-end;
}

.launch-btn {
    background-color: var(--bg-color);
    color: var(--primary-color);
    border: 1px solid var(--border-color);
    padding: 0.4rem 1rem;
    border-radius: 8px;
    font-size: 0.8rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.site-card:hover .launch-btn {
    background: var(--gradient-brand);
    color: #ffffff;
    border-color: transparent;
    box-shadow: 0 4px 10px rgba(59, 130, 246, 0.3);
}

/* --- フッター --- */
footer {
    text-align: center;
    padding: 2rem;
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 500;
    margin-top: auto;
}

.days-left {
    margin-top: 0.5rem;
    font-size: 0.85rem;
    color: var(--text-color);
    font-weight: 600;
}

/* --- レスポンシブ --- */
@media (max-width: 1200px) {
    .hidden-mobile {
        display: none !important;
    }
}

@media (max-width: 768px) {
    .site-grid {
        grid-template-columns: 1fr;
        gap: 1.2rem;
    }
    
    .header-container {
        flex-direction: column;
        align-items: center;
        gap: 0.8rem;
        padding: 0.5rem 1rem;
    }
    
    .header-center {
        width: 100%;
        flex-direction: row;
        justify-content: space-between;
        background: var(--card-bg);
        padding: 0.5rem 1rem;
        border-radius: 12px;
        box-shadow: 0 2px 8px var(--shadow-color);
    }
    
    .header-right {
        width: 100%;
        justify-content: space-between;
    }

    main {
        padding: 1rem;
    }
}