/* ============================================
   学习检测 APP - 全局样式 v3
   Design System: Apple (SF Style)
   学生端(蓝色系) + 家长端(橙色系)
   响应式: 移动端(320-428px) + 桌面端(768px+)
   ============================================ */

/* ---------- Apple Design Tokens ---------- */
:root {
    /* Brand Blue */
    --brand-50: #e8f2ff;
    --brand-100: #cfe5ff;
    --brand-200: #9fcbff;
    --brand-300: #66abff;
    --brand-400: #2e8dff;
    --brand-500: #007aff;
    --brand-600: #0064d6;
    --brand-700: #004fad;
    --brand-800: #003b82;
    --brand-900: #00275a;

    /* Background */
    --bg-50: #ffffff;
    --bg-100: #f7f7fa;
    --bg-200: #f2f2f7;
    --bg-300: #e5e5ea;
    --bg-400: #d1d1d6;
    --bg-500: #aeaeb2;
    --bg-600: #8e8e93;
    --bg-700: #3a3a3c;
    --bg-800: #1c1c1e;
    --bg-900: #000000;

    /* Text */
    --text-50: #f5f5f7;
    --text-100: #e3e3e8;
    --text-200: #c7c7cc;
    --text-300: #aeaeb2;
    --text-400: #8e8e93;
    --text-500: #6e6e73;
    --text-600: #48484a;
    --text-700: #3c3c43;
    --text-800: #1d1d1f;
    --text-900: #000000;

    /* Semantic */
    --success: #34c759;
    --success-bg: rgba(52, 199, 89, 0.12);
    --warning: #ff9f0a;
    --warning-bg: rgba(255, 159, 10, 0.12);
    --danger: #ff3b30;
    --danger-bg: rgba(255, 59, 48, 0.12);
    --info: #5ac8fa;

    /* Student primary = brand blue */
    --primary: var(--brand-500);
    --primary-dark: var(--brand-600);
    --primary-light: var(--brand-400);
    --primary-gradient: linear-gradient(135deg, var(--brand-500) 0%, var(--brand-400) 50%, var(--brand-300) 100%);
    --primary-gradient-solid: linear-gradient(135deg, var(--brand-500) 0%, var(--brand-600) 100%);
    --primary-glow: rgba(0, 122, 255, 0.3);

    /* Parent primary = orange */
    --parent-primary: #ff9500;
    --parent-primary-dark: #e08600;
    --parent-primary-light: #ffad33;
    --parent-gradient: linear-gradient(135deg, #ff9500 0%, #ffad33 50%, #ffc24d 100%);
    --parent-gradient-solid: linear-gradient(135deg, #ff9500 0%, #e08600 100%);
    --parent-glow: rgba(255, 149, 0, 0.3);

    /* Derived */
    --bg: var(--bg-200);
    --bg-card: var(--bg-50);
    --text-primary: var(--text-900);
    --text-secondary: var(--text-700);
    --text-hint: var(--text-500);
    --border: var(--bg-300);
    --border-light: var(--bg-200);

    /* Apple Radius (SF Rounded) */
    --radius-xs: 8px;
    --radius-sm: 12px;
    --radius-md: 16px;
    --radius-lg: 20px;
    --radius-xl: 24px;
    --radius-2xl: 28px;
    --radius-full: 50%;

    /* Apple Shadows */
    --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.16);
    --shadow-glow-brand: 0 4px 20px var(--primary-glow);
    --shadow-glow-parent: 0 4px 20px var(--parent-glow);

    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'SF Pro Text', 'PingFang SC', 'Helvetica Neue', 'Noto Sans SC', sans-serif;

    /* Apple Easing (spring-like) */
    --ease-out: cubic-bezier(0.25, 0.1, 0.25, 1);
    --ease-in-out: cubic-bezier(0.42, 0, 0.58, 1);
    --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
    --ease-bounce: cubic-bezier(0.36, 1.7, 0.5, 1);
    --ease-decelerate: cubic-bezier(0, 0, 0.2, 1);
    --ease-apple: cubic-bezier(0.28, 0.11, 0.32, 1);
}

/* ---------- Splash Screen ---------- */
.splash-screen {
    position: fixed;
    inset: 0;
    z-index: 9999;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: var(--primary-gradient-solid);
    overflow: hidden;
}

.splash-screen.parent-splash {
    background: var(--parent-gradient-solid);
}

.splash-bg-circle {
    position: absolute;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.08);
    animation: splashPulse 3s ease-in-out infinite;
}

.splash-bg-circle:nth-child(1) {
    width: 400px; height: 400px;
    top: -120px; right: -100px;
}

.splash-bg-circle:nth-child(2) {
    width: 280px; height: 280px;
    bottom: -80px; left: -80px;
    animation-delay: 1s;
}

.splash-bg-circle:nth-child(3) {
    width: 160px; height: 160px;
    top: 35%; left: 8%;
    animation-delay: 2s;
}

.splash-logo {
    width: 108px; height: 108px;
    background: rgba(255, 255, 255, 0.18);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-radius: 26px;
    display: flex; align-items: center; justify-content: center;
    font-size: 52px;
    box-shadow: 0 8px 40px rgba(0, 0, 0, 0.15);
    animation: splashLogoIn 0.9s var(--ease-spring) both;
    position: relative; z-index: 1;
}

.splash-title {
    color: white;
    font-family: var(--font-sans);
    font-size: 28px;
    font-weight: 700;
    margin-top: 24px;
    letter-spacing: -0.5px;
    animation: splashTitleIn 0.7s var(--ease-apple) 0.3s both;
    position: relative; z-index: 1;
}

.splash-subtitle {
    color: rgba(255, 255, 255, 0.7);
    font-size: 14px;
    margin-top: 8px;
    font-weight: 400;
    animation: splashTitleIn 0.7s var(--ease-apple) 0.5s both;
    position: relative; z-index: 1;
}

.splash-loader {
    margin-top: 44px;
    width: 36px; height: 36px;
    border: 3px solid rgba(255, 255, 255, 0.2);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.7s linear infinite, splashTitleIn 0.5s var(--ease-apple) 0.7s both;
    position: relative; z-index: 1;
}

.splash-screen.fade-out {
    animation: splashFadeOut 0.6s var(--ease-out) forwards;
}

@keyframes splashPulse {
    0%, 100% { transform: scale(1); opacity: 1; }
    50% { transform: scale(1.1); opacity: 0.6; }
}

@keyframes splashLogoIn {
    from { opacity: 0; transform: scale(0.5) translateY(30px); }
    to { opacity: 1; transform: scale(1) translateY(0); }
}

@keyframes splashTitleIn {
    from { opacity: 0; transform: translateY(18px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes splashFadeOut {
    from { opacity: 1; transform: scale(1); }
    to { opacity: 0; transform: scale(1.05); pointer-events: none; }
}

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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    background: var(--bg);
    color: var(--text-primary);
    font-size: 15px;
    line-height: 1.47;
    overflow-x: hidden;
    min-height: 100vh;
}

::-webkit-scrollbar { width: 3px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--bg-400); border-radius: 3px; }

/* ---------- Page System ---------- */
.page {
    min-height: 100vh;
    padding-bottom: 84px;
    display: none;
    animation: pageSlideIn 0.45s var(--ease-apple);
}

.page.active { display: block; }

/* ---------- Header ---------- */
.header {
    background: var(--primary-gradient-solid);
    color: white;
    padding: 56px 20px 20px;
    position: sticky;
    top: 0;
    z-index: 100;
}

.header::after {
    content: '';
    position: absolute;
    bottom: -16px;
    left: 0; right: 0;
    height: 16px;
    background: var(--primary-gradient-solid);
    clip-path: ellipse(60% 100% at 50% 0%);
    pointer-events: none;
}

.header h1 {
    font-size: 28px;
    font-weight: 700;
    letter-spacing: -0.5px;
}

.header .subtitle {
    font-size: 15px;
    opacity: 0.8;
    margin-top: 4px;
    font-weight: 400;
}

/* ---------- Container ---------- */
.container { padding: 20px 16px; }

/* ---------- Card ---------- */
.card {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: 18px;
    margin-bottom: 12px;
    box-shadow: var(--shadow-xs);
    animation: cardScaleIn 0.5s var(--ease-spring);
    transition: transform 0.4s var(--ease-spring), box-shadow 0.3s var(--ease-out);
}

.card:hover {
    box-shadow: var(--shadow-sm);
}

.card:active {
    transform: scale(0.97);
    box-shadow: var(--shadow-xs);
}

/* ---------- Buttons (Apple Pill Style) ---------- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 32px;
    border-radius: 22px;
    border: none;
    font-size: 16px;
    font-weight: 600;
    font-family: var(--font-sans);
    cursor: pointer;
    transition: transform 0.35s var(--ease-spring), box-shadow 0.3s var(--ease-out), opacity 0.2s;
    text-align: center;
    letter-spacing: -0.2px;
    position: relative;
    overflow: hidden;
    -webkit-user-select: none;
    user-select: none;
}

/* Apple haptic-like press effect */
.btn:active {
    transform: scale(0.96);
    opacity: 0.85;
}

.btn-primary {
    background: var(--primary-gradient-solid);
    color: white;
    width: 100%;
    box-shadow: var(--shadow-glow-brand);
    border-radius: 14px;
}

.btn-primary:active {
    box-shadow: 0 2px 10px var(--primary-glow);
}

.btn-secondary {
    background: var(--bg-300);
    color: var(--text-800);
}

.btn-secondary:active {
    background: var(--bg-400);
}

.btn-success {
    background: linear-gradient(135deg, #34c759 0%, #28a745 100%);
    color: white;
    box-shadow: 0 4px 16px rgba(52, 199, 89, 0.3);
    border-radius: 22px;
    padding: 13px 28px;
    font-weight: 600;
}

.btn-outline {
    background: transparent;
    border: 2px solid var(--brand-500);
    color: var(--brand-500);
}

.btn-logout {
    margin: 28px 16px;
    background: linear-gradient(135deg, var(--danger) 0%, #cc2d25 100%);
    color: white;
    width: calc(100% - 32px);
    box-shadow: 0 4px 16px rgba(255, 59, 48, 0.25);
    border-radius: 14px;
}

/* ---------- Form ---------- */
.form-group { margin-bottom: 18px; }

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-size: 13px;
    color: var(--text-600);
    font-weight: 600;
    letter-spacing: 0.2px;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 14px 16px;
    border: 1.5px solid var(--bg-300);
    border-radius: var(--radius-sm);
    font-size: 16px;
    font-family: var(--font-sans);
    transition: border-color 0.3s var(--ease-out), box-shadow 0.3s var(--ease-out), transform 0.2s var(--ease-spring);
    background: var(--bg-50);
    color: var(--text-900);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-400);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--brand-500);
    box-shadow: 0 0 0 4px rgba(0, 122, 255, 0.15);
    transform: scale(1.01);
}

.form-group textarea {
    resize: vertical;
    min-height: 80px;
}

/* ---------- Bottom Navigation ---------- */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0; right: 0;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    display: flex;
    box-shadow: 0 -0.5px 0 var(--bg-300);
    z-index: 100;
    animation: navSlideUp 0.5s var(--ease-apple);
    padding-bottom: env(safe-area-inset-bottom, 0);
}

.nav-item {
    flex: 1;
    padding: 8px 0 10px;
    text-align: center;
    cursor: pointer;
    color: var(--text-500);
    transition: color 0.3s var(--ease-out), transform 0.4s var(--ease-spring);
    position: relative;
    -webkit-user-select: none;
    user-select: none;
}

.nav-item .icon {
    font-size: 24px;
    margin-bottom: 3px;
    transition: transform 0.4s var(--ease-spring);
}

.nav-item .label {
    font-size: 10px;
    font-weight: 500;
    letter-spacing: 0.1px;
}

.nav-item.active { color: var(--brand-500); }

.nav-item.active .icon {
    transform: scale(1.15) translateY(-1px);
}

.nav-item:active {
    transform: scale(0.88);
}

/* Parent nav */
.parent-nav .nav-item.active { color: var(--parent-primary); }

/* ---------- Loading & Toast ---------- */
.loading {
    display: none;
    text-align: center;
    padding: 32px;
}

.loading.active {
    display: block;
    animation: fadeIn 0.3s var(--ease-out);
}

.spinner {
    display: inline-block;
    width: 32px; height: 32px;
    border: 3px solid var(--bg-300);
    border-top-color: var(--brand-500);
    border-radius: 50%;
    animation: spin 0.7s linear infinite;
}

.toast {
    position: fixed;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%) scale(0.85);
    background: rgba(28, 28, 30, 0.88);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    color: white;
    padding: 14px 28px;
    border-radius: var(--radius-md);
    z-index: 1000;
    display: none;
    max-width: 80%;
    text-align: center;
    font-size: 15px;
    font-weight: 500;
}

.toast.show {
    display: block;
    animation: toastSpringIn 0.45s var(--ease-spring);
}

/* ---------- Login Page ---------- */
.login-page {
    min-height: 100vh;
    background: var(--primary-gradient-solid);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    position: relative;
    overflow: hidden;
}

.login-page::before {
    content: '';
    position: absolute;
    width: 360px; height: 360px;
    background: rgba(255, 255, 255, 0.06);
    border-radius: 50%;
    top: -100px; right: -80px;
}

.login-page::after {
    content: '';
    position: absolute;
    width: 240px; height: 240px;
    background: rgba(255, 255, 255, 0.04);
    border-radius: 50%;
    bottom: -60px; left: -60px;
}

.login-card {
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(40px);
    -webkit-backdrop-filter: blur(40px);
    border-radius: var(--radius-2xl);
    padding: 40px 32px 32px;
    width: 100%;
    max-width: 400px;
    box-shadow: var(--shadow-xl);
    position: relative; z-index: 1;
    animation: loginSpringIn 0.8s var(--ease-spring);
}

.login-logo {
    text-align: center;
    margin-bottom: 32px;
}

.login-logo h2 {
    font-size: 22px;
    color: var(--text-900);
    margin-top: 16px;
    font-weight: 700;
    letter-spacing: -0.3px;
}

.login-toggle {
    text-align: center;
    margin-top: 24px;
    color: var(--brand-500);
    cursor: pointer;
    font-size: 15px;
    font-weight: 500;
    transition: opacity 0.2s;
}

.login-toggle:active { opacity: 0.6; }

/* ---------- Mode Cards ---------- */
.mode-card {
    position: relative;
    overflow: hidden;
    border-radius: var(--radius-lg);
}

.mode-card::after {
    content: '';
    position: absolute;
    top: 0; right: 0;
    width: 120px; height: 120px;
    border-radius: 50%;
    background: rgba(0, 0, 0, 0.03);
    transform: translate(30%, -30%);
}

.mode-card:active {
    transform: scale(0.96) !important;
    transition: transform 0.3s var(--ease-spring);
}

/* ---------- Welcome Card ---------- */
.welcome-card {
    background: var(--primary-gradient);
    color: white;
    border-radius: var(--radius-lg);
    padding: 28px 24px;
    margin-bottom: 16px;
    position: relative;
    overflow: hidden;
    box-shadow: 0 6px 28px var(--primary-glow);
    animation: cardScaleIn 0.6s var(--ease-spring);
}

.welcome-card::before {
    content: '';
    position: absolute;
    width: 200px; height: 200px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    top: -70px; right: -50px;
}

.welcome-card::after {
    content: '';
    position: absolute;
    width: 100px; height: 100px;
    background: rgba(255, 255, 255, 0.06);
    border-radius: 50%;
    bottom: -30px; left: 20px;
}

.welcome-card h2 {
    font-size: 24px;
    margin-bottom: 8px;
    position: relative; z-index: 1;
}

.welcome-card p {
    opacity: 0.88;
    font-size: 15px;
    position: relative; z-index: 1;
    line-height: 1.6;
}

.welcome-card .btn { position: relative; z-index: 1; }

/* ---------- Quick Actions ---------- */
.quick-action {
    display: flex;
    gap: 12px;
    margin-bottom: 20px;
}

.quick-btn {
    flex: 1;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: 22px 14px;
    text-align: center;
    box-shadow: var(--shadow-xs);
    cursor: pointer;
    transition: transform 0.4s var(--ease-spring), box-shadow 0.3s var(--ease-out);
    -webkit-user-select: none;
    user-select: none;
}

.quick-btn:active {
    transform: scale(0.93);
    box-shadow: var(--shadow-sm);
}

.quick-btn .icon {
    font-size: 36px;
    margin-bottom: 10px;
    display: block;
}

.quick-btn .label {
    font-size: 13px;
    color: var(--text-800);
    font-weight: 600;
}

/* ---------- Section Title ---------- */
.section-title {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 14px;
    color: var(--text-900);
    display: flex;
    align-items: center;
    justify-content: space-between;
    letter-spacing: -0.3px;
    animation: fadeIn 0.35s var(--ease-out);
}

.section-title .more {
    font-size: 14px;
    color: var(--text-500);
    font-weight: 500;
    cursor: pointer;
}

/* ---------- Question Items ---------- */
.question-item {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: 14px;
    margin-bottom: 12px;
    display: flex;
    gap: 14px;
    box-shadow: var(--shadow-xs);
    cursor: pointer;
    transition: transform 0.4s var(--ease-spring), box-shadow 0.3s var(--ease-out);
    animation: cardScaleIn 0.5s var(--ease-spring);
}

.question-item:active {
    transform: scale(0.97);
}

.question-item img {
    width: 80px; height: 80px;
    object-fit: cover;
    border-radius: var(--radius-sm);
    background: var(--bg-200);
}

.question-info {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.question-info .subject {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-900);
}

.question-info .time {
    font-size: 13px;
    color: var(--text-500);
}

/* ---------- Badges ---------- */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.2px;
}

.badge-primary {
    background: rgba(0, 122, 255, 0.12);
    color: var(--brand-500);
}

.badge-success {
    background: var(--success-bg);
    color: var(--success);
}

.badge-warning {
    background: var(--warning-bg);
    color: var(--warning);
}

.badge-danger {
    background: var(--danger-bg);
    color: var(--danger);
}

/* ---------- Search Header ---------- */
.search-header {
    background: var(--primary-gradient-solid);
    color: white;
    padding: 52px 18px 18px;
    display: flex;
    align-items: center;
    gap: 12px;
    position: relative;
    z-index: 1;
}

.search-header::after {
    content: '';
    position: absolute;
    bottom: -16px;
    left: 0; right: 0;
    height: 16px;
    background: var(--primary-gradient-solid);
    clip-path: ellipse(60% 100% at 50% 0%);
    pointer-events: none;
}

.back-btn {
    font-size: 22px;
    cursor: pointer;
    width: 40px; height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.15);
    transition: transform 0.3s var(--ease-spring), background 0.2s;
    backdrop-filter: blur(4px);
}

.back-btn:active {
    transform: scale(0.85);
    background: rgba(255, 255, 255, 0.3);
}

.search-header h2 {
    flex: 1;
    font-size: 17px;
    text-align: center;
    margin-right: 40px;
    font-weight: 600;
}

/* ---------- Search Upload ---------- */
.search-image-upload {
    background: var(--bg-card);
    margin: 16px 14px;
    border-radius: var(--radius-md);
    padding: 24px;
    text-align: center;
    box-shadow: var(--shadow-xs);
    border: 2px dashed var(--bg-300);
    transition: border-color 0.3s, box-shadow 0.3s, transform 0.2s var(--ease-spring);
}

.search-image-upload.has-image {
    border-style: solid;
    border-color: var(--brand-400);
    box-shadow: 0 0 0 4px rgba(0, 122, 255, 0.08);
}

.image-preview {
    width: 100%;
    max-height: 300px;
    object-fit: contain;
    border-radius: var(--radius-sm);
    margin-bottom: 16px;
    display: none;
    background: var(--bg-200);
}

.image-preview.show {
    display: block;
    animation: cardScaleIn 0.4s var(--ease-spring);
}

.upload-btns { display: flex; gap: 12px; }

.upload-btn {
    flex: 1;
    padding: 14px;
    border-radius: 22px;
    border: none;
    font-size: 15px;
    font-weight: 600;
    font-family: var(--font-sans);
    cursor: pointer;
    transition: transform 0.35s var(--ease-spring), opacity 0.2s;
}

.upload-btn:active {
    transform: scale(0.94);
    opacity: 0.85;
}

.upload-btn.camera {
    background: var(--primary-gradient-solid);
    color: white;
    box-shadow: var(--shadow-glow-brand);
}

.upload-btn.gallery {
    background: linear-gradient(135deg, #34c759 0%, #28a745 100%);
    color: white;
    box-shadow: 0 4px 14px rgba(52, 199, 89, 0.25);
}

/* ---------- Answer Section ---------- */
.answer-section {
    background: var(--bg-card);
    margin: 14px;
    border-radius: var(--radius-md);
    padding: 20px;
    box-shadow: var(--shadow-xs);
    animation: cardScaleIn 0.5s var(--ease-spring);
}

.answer-section h3 {
    font-size: 17px;
    margin-bottom: 14px;
    color: var(--text-900);
    font-weight: 700;
}

.answer-content {
    background: var(--bg-200);
    padding: 20px;
    border-radius: var(--radius-sm);
    line-height: 1.8;
    white-space: pre-wrap;
    font-size: 15px;
    color: var(--text-800);
    border-left: 3px solid var(--brand-500);
}

/* ---------- Knowledge Points ---------- */
.knowledge-points { margin-top: 14px; }

.knowledge-points .point {
    padding: 12px 0;
    border-bottom: 1px solid var(--bg-200);
    font-size: 15px;
    color: var(--text-700);
    line-height: 1.6;
    animation: fadeIn 0.35s var(--ease-out);
}

.knowledge-points .point:last-child { border-bottom: none; }

/* ---------- Empty State ---------- */
.empty-state {
    text-align: center;
    padding: 64px 24px;
    color: var(--text-500);
}

.empty-state .icon {
    font-size: 72px;
    margin-bottom: 18px;
    animation: floatApple 4s ease-in-out infinite;
}

.empty-state p {
    font-size: 16px;
    font-weight: 500;
}

/* ---------- Profile Header ---------- */
.profile-header {
    background: var(--primary-gradient-solid);
    color: white;
    padding: 52px 20px 68px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.profile-header::before {
    content: '';
    position: absolute;
    width: 240px; height: 240px;
    background: rgba(255, 255, 255, 0.06);
    border-radius: 50%;
    top: -80px; right: -60px;
}

.avatar {
    width: 88px; height: 88px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    margin: 0 auto 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 40px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
}

.profile-header h2 {
    font-size: 22px;
    margin-bottom: 6px;
    font-weight: 700;
}

.profile-header .username {
    font-size: 14px;
    opacity: 0.8;
}

/* ---------- Stats Card ---------- */
.stats-card {
    background: var(--bg-card);
    margin: -36px 16px 22px;
    border-radius: var(--radius-md);
    padding: 24px 20px;
    display: flex;
    box-shadow: var(--shadow-lg);
    position: relative; z-index: 2;
    animation: cardScaleIn 0.6s var(--ease-spring) 0.1s both;
}

.stat-item {
    flex: 1;
    text-align: center;
    position: relative;
}

.stat-item:not(:last-child)::after {
    content: '';
    position: absolute;
    right: 0;
    top: 6px; bottom: 6px;
    width: 1px;
    background: var(--bg-300);
}

.stat-item .num {
    font-size: 28px;
    font-weight: 800;
    color: var(--brand-500);
    line-height: 1.2;
}

.stat-item .label {
    font-size: 12px;
    color: var(--text-500);
    margin-top: 6px;
    font-weight: 500;
}

/* ---------- Menu List ---------- */
.menu-list {
    background: var(--bg-card);
    margin: 0 16px 16px;
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-xs);
}

.menu-item {
    padding: 16px 18px;
    display: flex;
    align-items: center;
    border-bottom: 0.5px solid var(--bg-200);
    cursor: pointer;
    transition: background-color 0.25s var(--ease-out);
}

.menu-item:last-child { border-bottom: none; }

.menu-item:active {
    background-color: var(--bg-200);
}

.menu-item .icon {
    font-size: 22px;
    margin-right: 14px;
    width: 28px;
    text-align: center;
}

.menu-item .text {
    flex: 1;
    font-size: 16px;
    color: var(--text-900);
    font-weight: 400;
}

.menu-item .arrow {
    color: var(--text-400);
    font-size: 16px;
}

/* ---------- Analysis Charts ---------- */
.analysis-chart {
    background: var(--bg-card);
    margin: 14px;
    border-radius: var(--radius-md);
    padding: 20px;
    box-shadow: var(--shadow-xs);
    animation: cardScaleIn 0.5s var(--ease-spring);
}

.chart-container {
    width: 100%;
    height: 260px;
    position: relative;
}

/* ---------- Detail Sections ---------- */
.detail-section {
    background: var(--bg-card);
    margin: 14px;
    border-radius: var(--radius-md);
    padding: 20px;
    box-shadow: var(--shadow-xs);
    animation: cardScaleIn 0.5s var(--ease-spring);
}

.detail-section h3 {
    font-size: 17px;
    margin-bottom: 14px;
    color: var(--text-900);
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 700;
}

.detail-section h3.weak { color: var(--danger); }
.detail-section h3.strong { color: var(--success); }
.detail-section h3.suggest { color: var(--brand-500); }
.detail-section h3.habit { color: var(--warning); }

.detail-content {
    line-height: 1.8;
    font-size: 15px;
    color: var(--text-700);
    white-space: pre-wrap;
}

.suggestion-item {
    padding: 12px 0;
    border-bottom: 0.5px solid var(--bg-200);
    font-size: 15px;
    color: var(--text-700);
    display: flex;
    gap: 10px;
    line-height: 1.6;
}

.suggestion-item:last-child { border-bottom: none; }

.suggestion-item .num {
    color: var(--brand-500);
    font-weight: 700;
    min-width: 20px;
}

.generate-btn {
    margin: 18px;
    width: calc(100% - 36px);
    padding: 16px;
    font-size: 17px;
}

/* ---------- History Items ---------- */
.history-item {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: 18px;
    margin-bottom: 12px;
    cursor: pointer;
    box-shadow: var(--shadow-xs);
    transition: transform 0.4s var(--ease-spring), box-shadow 0.3s var(--ease-out);
    animation: cardScaleIn 0.5s var(--ease-spring);
}

.history-item:active {
    transform: scale(0.97);
}

.history-item .title {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-900);
    margin-bottom: 6px;
}

.history-item .time {
    font-size: 13px;
    color: var(--text-500);
}

/* ---------- Student Select ---------- */
.student-select {
    background: var(--bg-card);
    margin: 14px;
    border-radius: var(--radius-md);
    padding: 20px;
    box-shadow: var(--shadow-xs);
    animation: cardScaleIn 0.5s var(--ease-spring);
}

.student-item {
    display: flex;
    align-items: center;
    padding: 14px;
    border-radius: var(--radius-sm);
    margin-bottom: 10px;
    cursor: pointer;
    border: 2px solid transparent;
    transition: all 0.35s var(--ease-spring);
}

.student-item:last-child { margin-bottom: 0; }

.student-item.active {
    border-color: var(--parent-primary);
    background: rgba(255, 149, 0, 0.06);
}

.student-item .avatar {
    width: 52px; height: 52px;
    font-size: 24px;
    margin: 0 14px 0 0;
    background: var(--parent-primary);
    color: white;
    border: none;
    box-shadow: var(--shadow-glow-parent);
}

.student-info .name {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-900);
}

.student-info .grade {
    font-size: 13px;
    color: var(--text-500);
    margin-top: 3px;
}

.bind-btn {
    color: var(--parent-primary);
    font-size: 14px;
    cursor: pointer;
    padding: 8px 16px;
    border: 1.5px solid var(--parent-primary);
    border-radius: 22px;
    font-weight: 600;
    transition: all 0.3s var(--ease-spring);
}

.bind-btn:active {
    transform: scale(0.94);
    opacity: 0.7;
}

/* ---------- Parent Styles ---------- */
.parent-header {
    background: var(--parent-gradient-solid);
}

.parent-header::after {
    background: var(--parent-gradient-solid);
}

.parent-btn {
    background: var(--parent-gradient-solid);
    box-shadow: var(--shadow-glow-parent);
}

.profile-header.parent-header {
    background: var(--parent-gradient-solid);
}

.profile-header.parent-header .stat-item .num {
    color: var(--parent-primary);
}

/* ============================================
   Animations (Apple-style spring & bounce)
   ============================================ */

@keyframes pageSlideIn {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes cardScaleIn {
    from {
        opacity: 0;
        transform: scale(0.92);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes loginSpringIn {
    0% {
        opacity: 0;
        transform: translateY(40px) scale(0.9);
    }
    60% {
        transform: translateY(-4px) scale(1.01);
    }
    100% {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

@keyframes toastSpringIn {
    0% {
        opacity: 0;
        transform: translate(-50%, -50%) scale(0.7);
    }
    60% {
        transform: translate(-50%, -50%) scale(1.05);
    }
    100% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1);
    }
}

@keyframes navSlideUp {
    from {
        transform: translateY(100%);
    }
    to {
        transform: translateY(0);
    }
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

@keyframes floatApple {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-14px); }
}

@keyframes shimmer {
    0% { background-position: -200% 0; }
    100% { background-position: 200% 0; }
}

/* Staggered card animations */
.detail-section:nth-child(1) { animation-delay: 0.05s; }
.detail-section:nth-child(2) { animation-delay: 0.1s; }
.detail-section:nth-child(3) { animation-delay: 0.15s; }
.detail-section:nth-child(4) { animation-delay: 0.2s; }
.detail-section:nth-child(5) { animation-delay: 0.25s; }
.detail-section:nth-child(6) { animation-delay: 0.3s; }

.analysis-chart:nth-child(1) { animation-delay: 0.05s; }
.analysis-chart:nth-child(2) { animation-delay: 0.12s; }
.analysis-chart:nth-child(3) { animation-delay: 0.19s; }

/* ============================================
   Desktop Responsive (>= 768px)
   ============================================ */

@media screen and (min-width: 768px) {
    body { background: var(--bg-300); }

    .page {
        max-width: 480px;
        margin: 0 auto;
        background: var(--bg);
        min-height: 100vh;
        box-shadow: var(--shadow-xl);
        position: relative;
    }

    .login-page, .splash-screen {
        max-width: 480px;
        margin: 0 auto;
    }

    .splash-screen {
        left: 50%;
        transform: translateX(-50%);
    }

    .login-card {
        border-radius: var(--radius-2xl);
        padding: 44px 36px 36px;
    }

    .bottom-nav {
        max-width: 480px;
        left: 50%;
        transform: translateX(-50%);
        border-radius: var(--radius-lg) var(--radius-lg) 0 0;
        box-shadow: 0 -0.5px 0 var(--bg-300), var(--shadow-sm);
    }

    .container { padding: 20px; }

    .stats-card { margin: -36px 20px 22px; }
    .menu-list { margin: 0 20px 16px; }

    .btn-logout {
        margin: 28px 20px;
        width: calc(100% - 40px);
    }

    .detail-section,
    .analysis-chart,
    .answer-section,
    .student-select,
    .search-image-upload {
        margin-left: 16px;
        margin-right: 16px;
    }
}

@media screen and (min-width: 1200px) {
    .page, .login-page { max-width: 430px; }
    .bottom-nav, .splash-screen { max-width: 430px; }
}

@media screen and (max-width: 359px) {
    .header h1 { font-size: 24px; }
    .header .subtitle { font-size: 13px; }
    .welcome-card { padding: 22px; }
    .welcome-card h2 { font-size: 20px; }
    .stats-card { padding: 18px; }
    .stat-item .num { font-size: 24px; }
    .login-card { padding: 32px 22px; }
    .splash-logo { width: 88px; height: 88px; font-size: 42px; }
    .splash-title { font-size: 24px; }
}