:root {
    --bg: #F5F1E8;
    --text: #3D4A3A;
    --accent: #7A9E7E;
    --success: #8FAE93;
    --muted: #9E9B8E;
}

/* 黑白模式 */
body.monochrome {
    --bg: #FFFFFF;
    --text: #000000;
    --accent: #666666;
    --success: #333333;
    --muted: #999999;
}

body.monochrome .sidebar {
    background: #000000;
    color: #FFFFFF;
}

body.monochrome .sidebar-subtitle {
    color: #CCCCCC;
}

body.monochrome .theme-item {
    color: rgba(255, 255, 255, 0.7);
}

body.monochrome .theme-item:hover {
    background: rgba(255, 255, 255, 0.1);
    color: #FFFFFF;
}

body.monochrome .theme-item.active {
    background: #333333;
    color: #FFFFFF;
}

body.monochrome .sidebar-title {
    color: rgba(255, 255, 255, 0.5);
}

body.monochrome .sidebar-toggle {
    background: #666666;
}

body.monochrome .sidebar-toggle:hover {
    background: #999999;
}

body.monochrome .word-tooltip {
    background: #000000;
    color: #FFFFFF;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

body.monochrome .word-tooltip .phonetic {
    color: #CCCCCC;
}

body.monochrome .word-tooltip .meaning {
    color: #FFFFFF;
}

body.monochrome .sentence-translation {
    background: rgba(0, 0, 0, 0.05);
    border-left-color: #666666;
}

body.monochrome .sentence-translation .label {
    color: #666666;
}

body.monochrome .char.wrong {
    color: #000000;
}

body.monochrome .char.learned::after {
    background: #666666;
}

body.monochrome .ripple {
    border-color: #666666;
}

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

body {
    background-color: var(--bg);
    color: var(--text);
    font-family: 'Inter', sans-serif;
    overflow: hidden;
    height: 100vh;
    display: flex;
    flex-direction: row;
}

/* 左侧侧边栏 */
.sidebar {
    width: 240px;
    height: 100vh;
    background: var(--text);
    color: var(--bg);
    display: flex;
    flex-direction: column;
    padding: 32px 24px;
    flex-shrink: 0;
    z-index: 50;
    position: relative;
    transition: width 0.3s ease;
}

.sidebar.collapsed {
    width: 60px;
    padding: 32px 12px;
}

/* 收起/展开按钮 */
.sidebar-toggle {
    position: absolute;
    top: 24px;
    right: -12px;
    width: 24px;
    height: 24px;
    background: var(--accent);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    z-index: 51;
}

.sidebar-toggle:hover {
    background: var(--success);
    transform: scale(1.1);
}

.toggle-icon {
    font-size: 10px;
    color: var(--bg);
    transition: transform 0.3s ease;
}

.sidebar.collapsed .toggle-icon {
    transform: rotate(180deg);
}

.sidebar-header {
    margin-bottom: 40px;
    transition: opacity 0.3s ease;
}

.sidebar.collapsed .sidebar-header {
    opacity: 0;
    pointer-events: none;
}

.sidebar-logo {
    font-size: 24px;
    font-weight: 900;
    letter-spacing: 0.1em;
    color: var(--bg);
}

.sidebar-subtitle {
    font-size: 11px;
    font-weight: 500;
    letter-spacing: 0.3em;
    color: var(--accent);
    margin-top: 4px;
}

.sidebar-section {
    flex: 1;
}

.sidebar-title {
    font-size: 11px;
    font-weight: 500;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: rgba(245, 241, 232, 0.5);
    margin-bottom: 16px;
    padding-left: 12px;
    transition: opacity 0.3s ease;
}

.sidebar.collapsed .sidebar-title {
    opacity: 0;
}

.theme-list {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.theme-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    color: rgba(245, 241, 232, 0.7);
}

.sidebar.collapsed .theme-item {
    padding: 12px 8px;
    justify-content: center;
}

.theme-item:hover {
    background: rgba(245, 241, 232, 0.08);
    color: var(--bg);
}

.theme-item.active {
    background: var(--accent);
    color: var(--bg);
}

.theme-icon {
    font-size: 14px;
    width: 20px;
    text-align: center;
    flex-shrink: 0;
}

.theme-name {
    font-size: 14px;
    font-weight: 500;
    transition: opacity 0.3s ease;
    white-space: nowrap;
}

.sidebar.collapsed .theme-name {
    opacity: 0;
    width: 0;
    overflow: hidden;
}

/* 主内容区域 */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    position: relative;
}

/* 瑞士网格系统 */
.swiss-container {
    width: 100%;
    max-width: 720px;
    margin: 0 auto;
    padding: 0 24px;
    position: relative;
}

/* 标题 - 温和尺度 */
.mega-headline {
    font-size: clamp(36px, 6vw, 72px);
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.1;
    color: var(--text);
    margin-bottom: 60px;
    position: relative;
    text-transform: uppercase;
}

.mega-headline::after {
    content: '';
    position: absolute;
    bottom: -20px;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--accent);
    transform: scaleX(0);
    transform-origin: left;
    animation: expandLine 1.2s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

@keyframes expandLine {
    to { transform: scaleX(1); }
}

/* 提示区域 - 绝对聚焦 */
.prompt-zone {
    position: relative;
    min-height: 200px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.prompt-label {
    font-size: 12px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.2em;
    color: var(--muted);
    margin-bottom: 24px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.prompt-label::before {
    content: '';
    width: 32px;
    height: 1px;
    background: var(--accent);
}

.prompt-text {
    font-family: 'JetBrains Mono', monospace;
    font-size: 28px;
    line-height: 1.6;
    color: var(--muted);
    letter-spacing: 0.02em;
    position: relative;
    white-space: pre-wrap;
    word-break: break-word;
}

.char {
    display: inline-block;
    position: relative;
    transition: all 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
    min-width: 1ch;
}

.char.correct {
    color: var(--text);
    transform: scale(1);
    text-shadow: 0 0 20px rgba(245, 245, 240, 0.1);
}

.char.wrong {
    color: var(--accent);
    animation: shake 0.4s cubic-bezier(0.36, 0, 0.66, -0.56) both;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-2px); }
    75% { transform: translateX(2px); }
}

.char.pending {
    color: var(--muted);
}

/* 呼吸光标 */
.cursor {
    position: absolute;
    width: 3px;
    height: 1.2em;
    background: var(--accent);
    animation: breathe 3s ease-in-out infinite;
    margin-left: -1.5px;
}

@keyframes breathe {
    0%, 100% { opacity: 1; transform: scaleY(1); }
    50% { opacity: 0.3; transform: scaleY(0.8); }
}

/* 输入遮罩层 */
.input-layer {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    cursor: text;
    z-index: 10;
}

/* 涟漪效果层 */
.ripple-layer {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1;
}

.ripple {
    position: absolute;
    border: 1px solid var(--accent);
    border-radius: 50%;
    opacity: 0;
    animation: rippleEffect 1.5s ease-out forwards;
}

@keyframes rippleEffect {
    0% { transform: scale(0); opacity: 0.15; }
    100% { transform: scale(4); opacity: 0; }
}

/* 侧边栏设置按钮 */
.sidebar-settings {
    position: relative;
    margin-top: auto;
    padding-top: 20px;
    border-top: 1px solid rgba(245, 241, 232, 0.1);
}

.settings-toggle-btn {
    width: 100%;
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    border-radius: 8px;
    background: transparent;
    border: none;
    color: rgba(245, 241, 232, 0.7);
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: inherit;
}

.settings-toggle-btn:hover {
    background: rgba(245, 241, 232, 0.08);
    color: var(--bg);
}

.settings-toggle-btn.active {
    background: var(--accent);
    color: var(--bg);
}

.settings-icon {
    font-size: 16px;
    width: 20px;
    text-align: center;
    flex-shrink: 0;
}

.settings-text {
    font-size: 14px;
    font-weight: 500;
    transition: opacity 0.3s ease;
    white-space: nowrap;
}

.sidebar.collapsed .settings-text {
    opacity: 0;
    width: 0;
    overflow: hidden;
}

.sidebar.collapsed .settings-toggle-btn {
    padding: 12px 8px;
    justify-content: center;
}

/* 设置下拉面板 */
.settings-dropdown {
    position: absolute;
    left: 100%;
    bottom: 0;
    width: 240px;
    background: var(--bg);
    border-radius: 16px;
    padding: 20px;
    margin-left: 12px;
    box-shadow: 0 8px 40px rgba(61, 74, 58, 0.2);
    opacity: 0;
    transform: translateX(-10px) scale(0.95);
    pointer-events: none;
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    border: 1px solid rgba(61, 74, 58, 0.1);
    z-index: 100;
}

.settings-dropdown.show {
    opacity: 1;
    transform: translateX(0) scale(1);
    pointer-events: auto;
}

.settings-dropdown-title {
    font-size: 10px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--muted);
    margin-bottom: 10px;
    padding-left: 4px;
}

.settings-options {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.settings-item {
    font-size: 12px;
    font-weight: 500;
    padding: 8px 14px;
    border-radius: 20px;
    background: rgba(61, 74, 58, 0.06);
    color: var(--text);
    cursor: pointer;
    transition: all 0.2s ease;
    user-select: none;
}

.settings-item:hover {
    background: rgba(61, 74, 58, 0.12);
}

.settings-item.active {
    background: var(--accent);
    color: var(--bg);
}

/* 旧控制栏和设置菜单样式隐藏 */
.controls,
.settings-menu {
    display: none;
}

/* 进度指示器 - 极简 */
.progress {
    position: fixed;
    top: 0;
    left: 0;
    height: 2px;
    background: var(--accent);
    width: 0%;
    transition: width 0.3s ease;
    z-index: 30;
}

/* 完成动画 - 放在句子右侧 */
.completion-message {
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%) scale(0.9);
    font-size: 14px;
    font-weight: 700;
    color: var(--success);
    opacity: 0;
    pointer-events: none;
    transition: all 0.6s cubic-bezier(0.16, 1, 0.3, 1);
    text-align: left;
    z-index: 40;
    padding-left: 40px;
    white-space: nowrap;
}

.completion-message.show {
    opacity: 1;
    transform: translateY(-50%) scale(1);
}

/* 禅模式覆盖 */
.zen-mode .prompt-label,
.zen-mode .mega-headline {
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.8s ease;
}

.zen-mode .controls {
    opacity: 0.15;
    transition: opacity 0.8s ease;
}

.zen-mode .controls:hover {
    opacity: 1;
}

.zen-mode .prompt-zone {
    transform: scale(1.1) translateY(-80px);
    transition: transform 0.8s ease;
}

/* 隐藏滚动条 */
::-webkit-scrollbar { display: none; }

/* 单词学习提示 */
.word-tooltip {
    position: absolute;
    background: var(--text);
    color: var(--bg);
    padding: 12px 16px;
    border-radius: 8px;
    font-size: 14px;
    line-height: 1.5;
    max-width: 280px;
    z-index: 100;
    opacity: 0;
    transform: translateY(10px) scale(0.95);
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    pointer-events: none;
    box-shadow: 0 4px 20px rgba(61, 74, 58, 0.15);
}

.word-tooltip.show {
    opacity: 1;
    transform: translateY(0) scale(1);
}

.word-tooltip .phonetic {
    font-family: 'JetBrains Mono', monospace;
    color: var(--success);
    font-size: 13px;
    margin-bottom: 4px;
}

.word-tooltip .meaning {
    color: var(--bg);
    font-size: 13px;
}

/* 句子翻译 */
.sentence-translation {
    margin-top: 32px;
    padding: 20px 24px;
    background: rgba(122, 158, 126, 0.08);
    border-left: 3px solid var(--accent);
    border-radius: 0 8px 8px 0;
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.sentence-translation.show {
    opacity: 1;
    transform: translateY(0);
}

.sentence-translation .label {
    font-size: 11px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--accent);
    margin-bottom: 8px;
}

.sentence-translation .text {
    font-size: 18px;
    color: var(--text);
    line-height: 1.6;
}

/* 已学习单词高亮 */
.char.learned {
    position: relative;
}

.char.learned::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--accent);
    opacity: 0.4;
}

.sentence-nav {
    position: fixed;
    top: 40px;
    right: 40px;
    display: flex;
    align-items: center;
    gap: 12px;
    z-index: 20;
}

.sentence-nav-btn {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    border: 1px solid var(--muted);
    background: transparent;
    color: var(--muted);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}

.sentence-nav-btn:hover {
    background: var(--accent);
    border-color: var(--accent);
    color: var(--bg);
    transform: scale(1.1);
}

.sentence-nav-btn:active {
    transform: scale(0.95);
}

.sentence-nav-btn svg {
    width: 14px;
    height: 14px;
}

body.monochrome .sentence-nav-btn {
    border-color: #999;
    color: #999;
}

body.monochrome .sentence-nav-btn:hover {
    background: #333;
    border-color: #333;
    color: #FFF;
}

.prompt-counter {
    font-size: 11px;
    color: var(--muted);
    letter-spacing: 0.1em;
}