@import url('https://fonts.googleapis.com/css2?family=Baloo+2:wght@400;500;600;700&family=ZCOOL+KuaiLe&display=swap');

:root {
    --color-primary: #FF6B6B;
    --color-primary-light: #FF8E8E;
    --color-primary-dark: #FF5252;
    --color-secondary: #4ECDC4;
    --color-accent: #FFE66D;
    --color-accent-light: #95E1D3;
    --color-background: #FFF9E6;
    --color-surface: #FFFFFF;
    --color-foreground: #5D5D5D;
    --color-text-secondary: #8B8B8B;
    --color-muted: #FFF0F0;
    --color-border: #FFE4E4;
    --color-success: #4ECDC4;
    --color-error: #FF6B6B;
    --color-warning: #FFE66D;
    --color-ring: #FF6B6B;

    --shadow-xs: 0 2px 4px rgba(255, 107, 107, 0.08);
    --shadow-sm: 0 4px 8px rgba(255, 107, 107, 0.12);
    --shadow-md: 0 6px 16px rgba(255, 107, 107, 0.16);
    --shadow-lg: 0 10px 24px rgba(255, 107, 107, 0.20);
    --shadow-xl: 0 14px 32px rgba(255, 107, 107, 0.24);

    --radius-xs: 12px;
    --radius-sm: 16px;
    --radius-md: 20px;
    --radius-lg: 24px;
    --radius-xl: 32px;
    --radius-full: 9999px;

    --space-xs: 6px;
    --space-sm: 10px;
    --space-md: 16px;
    --space-lg: 20px;
    --space-xl: 28px;
    --space-2xl: 40px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
    height: 100%;
}

body {
    font-family: 'Baloo 2', 'Noto Sans SC', 'Microsoft YaHei', sans-serif;
    background: var(--color-background);
    min-height: 100%;
    color: var(--color-foreground);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    padding: 0;
    padding-bottom: 80px;
}

/* App Container */
.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    max-width: 100%;
    margin: 0 auto;
}

/* Header */
.app-header {
    background: linear-gradient(135deg, #FF6B6B 0%, #FF8E53 100%);
    padding: var(--space-lg);
    padding-top: calc(var(--space-lg) + env(safe-area-inset-top, 0px));
    box-shadow: var(--shadow-lg);
    position: sticky;
    top: 0;
    z-index: 100;
}

.app-header-content {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.app-header-icon {
    width: 52px;
    height: 52px;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 36px;
}

.app-header-icon svg {
    width: 100%;
    height: 100%;
    filter: drop-shadow(0 2px 3px rgba(0,0,0,0.1));
}

.app-header-text {
    flex: 1;
}

.app-header-title {
    font-size: 28px;
    font-weight: 700;
    font-family: 'Noto Sans SC', 'Microsoft YaHei', 'SimHei', sans-serif;
    color: #FFFFFF;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.app-header-subtitle {
    font-size: 13px;
    color: rgba(255, 255, 255, 0.85);
    margin-top: 2px;
}

/* Main Content */
.app-content {
    flex: 1;
    padding: var(--space-lg);
}

/* 登录页面 */
.login-page {
    display: flex;
    flex-direction: column;
    justify-content: center;
    min-height: calc(100vh - 80px);
    padding: var(--space-xl);
}

.login-card {
    background: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--space-2xl);
    box-shadow: var(--shadow-xl);
    border: 3px solid var(--color-border);
}

.login-logo {
    text-align: center;
    margin-bottom: var(--space-2xl);
}

.login-logo-icon {
    width: 96px;
    height: 96px;
    background: linear-gradient(135deg, #FF6B6B 0%, #FF8E53 50%, #FFE66D 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 48px;
    box-shadow: var(--shadow-lg);
    color: white;
    margin: 0 auto var(--space-lg);
    box-shadow: var(--shadow-lg);
}

.login-title {
    font-size: 28px;
    font-weight: 700;
    color: var(--color-foreground);
    text-align: center;
}

.login-subtitle {
    font-size: 14px;
    color: var(--color-text-secondary);
    text-align: center;
    margin-top: var(--space-xs);
}

/* 表单 */
.form-group {
    margin-bottom: var(--space-lg);
}

.form-label {
    display: block;
    font-size: 15px;
    font-weight: 600;
    color: var(--color-foreground);
    margin-bottom: var(--space-sm);
}

.form-input {
    width: 100%;
    padding: var(--space-md) var(--space-lg);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: 16px;
    font-family: inherit;
    background: var(--color-muted);
    transition: all 0.2s ease;
    min-height: 52px;
}

.form-input:focus {
    outline: none;
    border-color: var(--color-primary);
    background: var(--color-surface);
    box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.15);
}

/* 按钮 */
.btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    width: 100%;
    padding: var(--space-md) var(--space-xl);
    border: none;
    border-radius: var(--radius-md);
    font-size: 17px;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: all 0.2s ease;
    min-height: 52px;
}

.btn-primary {
    background: linear-gradient(135deg, #FF6B6B 0%, #FF8E53 100%);
    color: white;
    box-shadow: var(--shadow-sm);
    border-radius: var(--radius-lg);
    font-weight: 600;
    font-size: 16px;
}

.btn-primary:active {
    transform: scale(0.96);
    box-shadow: var(--shadow-xs);
}

.btn-secondary {
    background: var(--color-muted);
    color: var(--color-foreground);
    border-radius: var(--radius-lg);
}

.btn-success {
    background: linear-gradient(135deg, #4ECDC4 0%, #44B8AF 100%);
    color: white;
    border-radius: var(--radius-lg);
}

.btn-danger {
    background: linear-gradient(135deg, #FF6B6B 0%, #FF5252 100%);
    color: white;
    border-radius: var(--radius-lg);
}

/* 卡片 */
.card {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
}

/* 进度统计 */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-md);
    margin-bottom: var(--space-xl);
}

.stat-card {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    border: 2px solid var(--color-border);
}

.stat-value {
    font-size: 32px;
    font-weight: 700;
    color: #FF6B6B;
    display: block;
    font-family: 'ZCOOL KuaiLe', 'Baloo 2', sans-serif;
}

.stat-label {
    font-size: 12px;
    color: var(--color-text-secondary);
    margin-top: 2px;
}

/* 汉字展示区 */
.char-display {
    background: linear-gradient(135deg, #FFF5E6 0%, #FFE4C9 100%);
    border-radius: var(--radius-xl);
    padding: var(--space-2xl) var(--space-lg);
    text-align: center;
    margin: var(--space-xl) 0;
    box-shadow: var(--shadow-lg);
    border: 3px solid #FFD4B8;
    min-height: 180px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.char-text {
    font-size: 96px;
    font-weight: 700;
    color: #FF6B6B;
    line-height: 1;
    font-family: 'Noto Sans SC', 'Microsoft YaHei', 'SimHei', sans-serif;
    text-shadow: 2px 2px 0px rgba(255, 107, 107, 0.2);
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-8px); }
}

/* 操作按钮组 */
.action-buttons {
    display: flex;
    gap: var(--space-xl);
    margin: var(--space-xl) 0;
}

.action-btn {
    flex: 1;
    padding: var(--space-lg);
    font-size: 20px;
    font-weight: 600;
    border-radius: var(--radius-xl);
    min-height: 64px;
    box-shadow: var(--shadow-md);
}

.action-btn.success {
    background: linear-gradient(135deg, #4ECDC4 0%, #44B8AF 100%);
    color: white;
}

.action-btn.danger {
    background: linear-gradient(135deg, #FF6B6B 0%, #FF5252 100%);
    color: white;
}

/* 空状态 */
.empty-state {
    text-align: center;
    padding: var(--space-2xl);
}

.empty-icon {
    width: 80px;
    height: 80px;
    background: var(--color-muted);
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 36px;
    margin: 0 auto var(--space-lg);
}

.empty-title {
    font-size: 20px;
    font-weight: 600;
    color: var(--color-foreground);
    margin-bottom: var(--space-sm);
}

.empty-text {
    font-size: 14px;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-xl);
}

/* 复习网格 */
.review-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-md);
    margin-top: var(--space-lg);
}

.review-item {
    aspect-ratio: 1;
    background: linear-gradient(135deg, #E8FFF3 0%, #D4F5E9 100%);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 36px;
    font-weight: 700;
    color: #4ECDC4;
    box-shadow: var(--shadow-md);
    border: 2px solid #B8E8DC;
    transition: all 0.2s ease;
    font-family: 'ZCOOL KuaiLe', 'Baloo 2', sans-serif;
}

.review-item:active {
    transform: scale(0.95);
    background: var(--color-success);
    color: white;
}

/* 底部导航 */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--color-surface);
    display: flex;
    justify-content: space-around;
    align-items: center;
    padding: var(--space-md) var(--space-lg);
    padding-bottom: calc(var(--space-md) + env(safe-area-inset-bottom, 0px));
    box-shadow: 0 -4px 20px rgba(79, 70, 229, 0.1);
    z-index: 100;
}

.nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--radius-lg);
    text-decoration: none;
    color: var(--color-text-secondary);
    font-size: 12px;
    font-weight: 500;
    transition: all 0.2s ease;
    min-width: 72px;
    position: relative;
    background: transparent;
    border: none;
    cursor: pointer;
}

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

.nav-item.active {
    color: #FF6B6B;
}

.nav-item.active::after {
    content: '';
    position: absolute;
    bottom: -6px;
    left: 50%;
    transform: translateX(-50%);
    width: 32px;
    height: 4px;
    background: linear-gradient(90deg, #FF6B6B, #FF8E53);
    border-radius: 4px;
}

.nav-icon {
    width: 24px;
    height: 24px;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.nav-item.active .nav-icon {
    color: var(--color-primary);
}

/* 消息提示 */
.message {
    text-align: center;
    padding: var(--space-md);
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 14px;
    margin-top: var(--space-md);
    display: none;
}

.message.show {
    display: block;
}

.message.success {
    background: #DCFCE7;
    color: #16A34A;
}

.message.error {
    background: #FEE2E2;
    color: #DC2626;
}

.message.info {
    background: #DBEAFE;
    color: #2563EB;
}

/* 响应式 */
@media (max-width: 400px) {
    .app-header {
        padding: var(--space-md);
    }
    
    .app-header-icon {
        width: 40px;
        height: 40px;
    }
    
    .app-header-title {
        font-size: 24px;
    }
    
    .app-header-subtitle {
        font-size: 12px;
    }
    
    .login-title {
        font-size: 24px;
    }
    
    .char-text {
        font-size: 72px;
    }
    
    .review-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* 安全区域 */
.safe-area-top {
    padding-top: env(safe-area-inset-top, 0px);
}

.safe-area-bottom {
    padding-bottom: env(safe-area-inset-bottom, 0px);
}