/* Start Screen Styles */
.start-content {
    max-width: 500px;
    background: linear-gradient(135deg, var(--panel-bg) 0%, var(--primary-light) 100%);
    border: 1px solid rgba(0,0,0,0.1);
}

.start-header {
    text-align: center;
    padding: 30px 20px 10px;
    border-bottom: none;
}

.start-header h1 {
    font-size: 32px;
    color: var(--primary-color);
    margin: 0;
    text-shadow: 2px 2px 0px var(--primary-shadow);
}

.start-header .subtitle {
    font-size: 14px;
    color: var(--text-secondary);
    letter-spacing: 2px;
    margin-top: 5px;
    text-transform: uppercase;
}

.start-body {
    padding: 20px 30px 40px;
}

.intro-text {
    text-align: center;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 30px;
    font-size: 15px;
}

.difficulty-section h3 {
    text-align: center;
    color: var(--text-primary);
    font-size: 16px;
    margin-bottom: 15px;
    position: relative;
    display: inline-block;
    width: 100%;
}

.difficulty-section h3::before,
.difficulty-section h3::after {
    content: "";
    position: absolute;
    top: 50%;
    width: 30%;
    height: 1px;
    background: #e2e8f0;
}
.difficulty-section h3::before { left: 0; }
.difficulty-section h3::after { right: 0; }

.difficulty-buttons {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.btn-difficulty {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    border: 2px solid #e2e8f0;
    border-radius: var(--radius-md);
    background: white;
    cursor: pointer;
    transition: all 0.2s;
    text-align: left;
}

.btn-difficulty:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    background: var(--primary-light, #fffbeb);
}

.btn-difficulty .diff-name {
    font-size: 16px;
    font-weight: 700;
    color: var(--text-primary);
}

.btn-difficulty .diff-desc {
    font-size: 12px;
    color: var(--text-secondary);
}

/* 难度颜色区分 */
.btn-difficulty[data-diff="EASY"]:hover { border-color: #10b981; background: #ecfdf5; }
.btn-difficulty[data-diff="MEDIUM"]:hover { border-color: var(--primary-color); background: var(--primary-light, #fffbeb); }
.btn-difficulty[data-diff="HARD"]:hover { border-color: #ef4444; background: #fef2f2; }
.btn-difficulty[data-diff="HELL"] { border-color: #1f2937; background: #1f2937; }
.btn-difficulty[data-diff="HELL"] .diff-name,
.btn-difficulty[data-diff="HELL"] .diff-desc { color: #f3f4f6; }
.btn-difficulty[data-diff="HELL"]:hover { 
    background: #000; 
    border-color: #000;
    transform: translateY(-2px) scale(1.02);
    box-shadow: 0 10px 20px -5px rgba(0,0,0,0.5);
}

/* ===== Theme Selection Styles ===== */
.theme-section {
    margin-bottom: 25px;
}

.theme-section h3 {
    text-align: center;
    color: var(--text-primary);
    font-size: 16px;
    margin-bottom: 15px;
    position: relative;
    display: inline-block;
    width: 100%;
}

.theme-section h3::before,
.theme-section h3::after {
    content: "";
    position: absolute;
    top: 50%;
    width: 30%;
    height: 1px;
    background: #e2e8f0;
}
.theme-section h3::before { left: 0; }
.theme-section h3::after { right: 0; }

.theme-buttons {
    display: flex;
    justify-content: center;
    gap: 16px;
}

.btn-theme {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    padding: 12px 20px;
    border: 2px solid #e2e8f0;
    border-radius: var(--radius-md);
    background: white;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-theme:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-theme.active {
    border-color: var(--primary-color);
    background: var(--primary-light, #fffbeb);
}

/* 各主题按钮的选中状态使用各自的颜色 */
.btn-theme[data-theme="amber"].active {
    border-color: #f59e0b;
    background: #fffbeb;
}
.btn-theme[data-theme="rose"].active {
    border-color: #ec4899;
    background: #fdf2f8;
}
.btn-theme[data-theme="sky"].active {
    border-color: #0ea5e9;
    background: #f0f9ff;
}

.theme-preview {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    box-shadow: var(--shadow-sm);
    border: 3px solid white;
}

/* 配色预览色块 */
.theme-preview.amber {
    background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
    box-shadow: 0 4px 12px rgba(245, 158, 11, 0.4);
}

.theme-preview.rose {
    background: linear-gradient(135deg, #ec4899 0%, #db2777 100%);
    box-shadow: 0 4px 12px rgba(236, 72, 153, 0.4);
}

.theme-preview.sky {
    background: linear-gradient(135deg, #0ea5e9 0%, #0284c7 100%);
    box-shadow: 0 4px 12px rgba(14, 165, 233, 0.4);
}

.theme-name {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
}

.btn-theme.active .theme-name {
    color: var(--primary-color);
}

/* 各主题按钮名称使用各自的颜色 */
.btn-theme[data-theme="amber"].active .theme-name { color: #f59e0b; }
.btn-theme[data-theme="rose"].active .theme-name { color: #ec4899; }
.btn-theme[data-theme="sky"].active .theme-name { color: #0ea5e9; }