/* General Resets and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-blue: #007bff; /* Standard blue */
    --accent-blue: #00bcd4; /* Brighter aqua/cyan */
    --dark-blue: #1a202c; /* Dark background */
    --text-light: #e2e8f0; /* Light gray text */
    --text-lighter: #f8fafc; /* Lighter gray text */
    --neon-glow: #00bcd4; /* Neon glow color */
    --gradient-start: #0f172a;
    --gradient-end: #1a202c;
}

body {
    font-family: 'Montserrat', 'Noto Sans SC', sans-serif;
    color: var(--text-light);
    background: linear-gradient(135deg, var(--gradient-start) 0%, var(--gradient-end) 100%);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    position: relative; /* For absolute positioning of background animation */
}

a {
    color: var(--accent-blue);
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: var(--text-lighter);
}

/* Background Animation - Stars/Particles */
.background-animation {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none; /* Allow clicks to pass through */
    z-index: -1; /* Send to background */
}

.star {
    position: absolute;
    background: rgba(255, 255, 255, 0.7);
    border-radius: 50%;
    animation: twinkle var(--twinkle-duration, 5s) infinite ease-in-out alternate,
    moveStar var(--move-duration, 20s) infinite linear;
    opacity: 0;
}

/* Animations remain the same, their durations are now set by JS variables */
@keyframes twinkle {
    0%, 100% { opacity: 0; transform: scale(0.8); }
    50% { opacity: 1; transform: scale(1.2); }
}

@keyframes moveStar {
    0% { transform: translate(0, 0); }
    25% { transform: translate(10vw, 5vh); }
    50% { transform: translate(20vw, -10vh); }
    75% { transform: translate(30vw, 15vh); }
    100% { transform: translate(0, 0); }
}

/* Header */
.main-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 2rem 5%;
    width: 100%;
    position: absolute; /* Position above other content */
    top: 0;
    left: 0;
    z-index: 10;
}

.logo {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-lighter);
    letter-spacing: 1px;
    display: flex;
    align-items: center;
    text-shadow: 0 0 15px rgba(0, 188, 212, 0.5); /* Neon glow for logo */
}

.logo i {
    font-size: 2.8rem;
    margin-right: 10px;
    color: var(--accent-blue);
    text-shadow: 0 0 10px var(--neon-glow);
}

.auth-nav {
    font-size: 1.1rem;
    display: flex;
    align-items: center;
}

.nav-text {
    color: var(--text-light);
    margin-right: 10px;
}

.login-link {
    padding: 8px 18px;
    border: 1px solid var(--accent-blue);
    border-radius: 5px;
    background-color: transparent;
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

.login-link:hover {
    background-color: var(--accent-blue);
    color: var(--dark-blue);
    border-color: var(--accent-blue);
}

/* Main Content Layout */
.main-content {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-grow: 1; /* Occupy remaining vertical space */
    padding: 2rem 5%;
    gap: 4rem; /* Space between left intro and right form */
    z-index: 1; /* Above background animation */
    position: relative; /* For z-indexing */
}

/* Introduction Section (Left Side) */
.intro-section {
    max-width: 550px;
    text-align: left;
    padding: 20px;
}

.intro-heading {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
    background: linear-gradient(90deg, #00bcd4, #8b5cf6); /* Gradient text */
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 0 20px rgba(0, 188, 212, 0.4);
}

.intro-subtext {
    font-size: 1.3rem;
    color: var(--text-light);
    margin-bottom: 2rem;
    line-height: 1.5;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1.5rem;
    margin-top: 3rem;
}

.feature-item {
    background: rgba(45, 55, 72, 0.3); /* Slightly darker transparent */
    backdrop-filter: blur(5px);
    border-radius: 12px;
    padding: 1.5rem;
    text-align: center;
    border: 1px solid rgba(0, 188, 212, 0.2);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
    transition: transform 0.3s ease, border-color 0.3s ease;
}

.feature-item:hover {
    transform: translateY(-8px);
    border-color: var(--accent-blue);
    box-shadow: 0 8px 30px rgba(0, 188, 212, 0.3);
}

.feature-item i {
    font-size: 2.5rem;
    color: var(--neon-glow);
    margin-bottom: 0.8rem;
    text-shadow: 0 0 10px rgba(0, 188, 212, 0.7);
}

.feature-item p {
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--text-lighter);
}

/* Registration Form Section (Right Side) */
.register-form-section {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100%; /* Ensure it takes full height for centering */
}

.form-card {
    background: rgba(26, 32, 44, 0.6); /* Semi-transparent dark blue */
    backdrop-filter: blur(15px); /* Stronger blur for glass effect */
    border-radius: 20px;
    padding: 3rem 2.5rem;
    width: 100%;
    max-width: 450px;
    border: 1px solid rgba(0, 188, 212, 0.3); /* Subtle neon border */
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.4), 0 0 30px rgba(0, 188, 212, 0.3); /* Depth + neon glow */
    transition: all 0.4s ease;
}

.form-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 50px rgba(0, 0, 0, 0.5), 0 0 40px rgba(0, 188, 212, 0.5);
}

.form-title {
    font-size: 2.2rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: 2rem;
    color: var(--text-lighter);
    text-shadow: 0 0 10px rgba(0, 188, 212, 0.6);
}

.input-group {
    position: relative;
    margin-bottom: 1.5rem;
}

.input-group i {
    position: absolute;
    left: 15px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--accent-blue);
    font-size: 1.2rem;
    text-shadow: 0 0 5px rgba(0, 188, 212, 0.5);
}

.input-group input {
    width: 100%;
    padding: 15px 15px 15px 50px; /* Adjust padding for icon */
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    background-color: rgba(255, 255, 255, 0.08); /* More transparent */
    color: var(--text-lighter);
    font-size: 1.05rem;
    outline: none;
    transition: border-color 0.3s ease, background-color 0.3s ease, box-shadow 0.3s ease;
}

.input-group input::placeholder {
    color: rgba(255, 255, 255, 0.5);
}

.input-group input:focus {
    border-color: var(--neon-glow);
    background-color: rgba(255, 255, 255, 0.15);
    box-shadow: 0 0 10px rgba(0, 188, 212, 0.5);
}

.verification-group {
    display: flex;
    align-items: center;
}

.verification-group input {
    flex-grow: 1; /* Take up available space */
    border-top-right-radius: 0;
    border-bottom-right-radius: 0;
    padding-right: 15px; /* Less space for icon since button is next */
}

.send-code-btn {
    background-color: var(--accent-blue);
    color: var(--dark-blue);
    border: none;
    padding: 15px 20px;
    border-radius: 8px;
    border-top-left-radius: 0;
    border-bottom-left-radius: 0;
    margin-left: -1px; /* Overlap border */
    cursor: pointer;
    font-size: 1.05rem;
    font-weight: 500;
    white-space: nowrap;
    transition: background-color 0.3s ease, transform 0.2s ease, box-shadow 0.3s ease;
    box-shadow: 0 0 15px rgba(0, 188, 212, 0.5);
}

.send-code-btn:hover:not(:disabled) {
    background-color: #00e5ff;
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(0, 188, 212, 0.7);
}

.send-code-btn:disabled {
    background-color: #555;
    cursor: not-allowed;
    box-shadow: none;
}

.checkbox-group {
    display: flex;
    align-items: flex-start; /* Align text to top of checkbox */
    margin-bottom: 2rem;
    font-size: 0.95rem;
    color: var(--text-light);
}

.checkbox-group input[type="checkbox"] {
    appearance: none; /* Hide default checkbox */
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    border: 1px solid var(--accent-blue);
    border-radius: 4px;
    background-color: rgba(0, 188, 212, 0.1);
    margin-right: 12px;
    cursor: pointer;
    position: relative;
    flex-shrink: 0; /* Prevent it from shrinking */
    transition: all 0.2s ease;
}

.checkbox-group input[type="checkbox"]:checked {
    background-color: var(--accent-blue);
    border-color: var(--accent-blue);
    box-shadow: 0 0 8px rgba(0, 188, 212, 0.7);
}

.checkbox-group input[type="checkbox"]:checked::after {
    content: '\2713'; /* Checkmark unicode */
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: var(--dark-blue);
    font-size: 1.2rem;
}

.checkbox-group label {
    line-height: 1.5;
}

.checkbox-group .terms-link {
    font-weight: 500;
    text-shadow: 0 0 5px rgba(0, 188, 212, 0.5);
}

.submit-btn {
    width: 100%;
    padding: 18px;
    background: linear-gradient(90deg, #00bcd4, #8b5cf6); /* Gradient button */
    color: var(--text-lighter);
    border: none;
    border-radius: 10px;
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    letter-spacing: 0.5px;
    box-shadow: 0 8px 30px rgba(0, 188, 212, 0.4), 0 0 20px rgba(139, 92, 246, 0.4);
    transition: all 0.3s ease;
}

.submit-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 12px 40px rgba(0, 188, 212, 0.6), 0 0 30px rgba(139, 92, 246, 0.6);
    filter: brightness(1.1);
}

/* Responsive Design */
@media (max-width: 1024px) {
    body {
        overflow-x: hidden; /* 只隐藏横向滚动条 */
        overflow-y: auto; /* 允许纵向滚动 */
    }
    
    .main-content {
        flex-direction: column;
        padding-top: 8rem;
        gap: 3rem;
        align-items: center;
        min-height: auto; /* 移除固定高度限制 */
        flex-grow: 0; /* 不强制占满剩余空间 */
    }

    .intro-section {
        text-align: center;
        max-width: 100%;
        padding: 1rem;
    }

    .intro-heading {
        font-size: 2.8rem;
    }

    .intro-subtext {
        font-size: 1.1rem;
    }

    .features-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
        margin-top: 2rem;
    }

    .register-form-section {
        width: 100%;
        max-width: 500px;
    }
}

@media (max-width: 768px) {
    body {
        overflow-x: hidden;
        overflow-y: auto;
    }

    .main-header {
        flex-direction: column;
        padding: 1.5rem 5%;
        align-items: center;
        text-align: center;
        position: relative; /* 改为相对定位，避免覆盖内容 */
    }

    .logo {
        font-size: 2rem;
        margin-bottom: 1rem;
    }

    .logo i {
        font-size: 2.3rem;
    }

    .auth-nav {
        font-size: 1rem;
        width: 100%;
        justify-content: center;
        margin-top: 0;
    }

    .auth-nav a {
        padding: 0.8rem 1.5rem;
        margin: 0 0.3rem;
    }

    .main-content {
        padding: 2rem 4% 3rem; /* 减少顶部间距 */
        gap: 2.5rem;
        min-height: auto;
        flex-grow: 0;
    }

    .intro-section {
        padding: 1.5rem 1rem;
    }

    .intro-heading {
        font-size: 2.4rem;
        line-height: 1.3;
        margin-bottom: 1.2rem;
    }

    .intro-subtext {
        font-size: 1rem;
        line-height: 1.6;
        margin-bottom: 1.8rem;
    }

    .features-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.2rem;
        margin-top: 1.5rem;
    }

    .feature-item {
        padding: 1.2rem 1rem;
        font-size: 0.9rem;
        border-radius: 10px;
    }

    .feature-item i {
        font-size: 2rem;
        margin-bottom: 0.8rem;
    }

    .form-card {
        padding: 2.5rem 2rem;
        max-width: 100%;
        margin: 0 0 2rem 0; /* 底部增加间距 */
        border-radius: 18px;
        box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4), 0 0 25px rgba(0, 188, 212, 0.25);
    }

    .form-title {
        font-size: 1.8rem;
        margin-bottom: 2rem;
    }

    .input-group {
        margin-bottom: 1.5rem;
    }

    .input-group input, .send-code-btn {
        font-size: 1rem;
        padding: 14px 16px;
        border-radius: 10px;
    }

    .input-group input {
        padding-left: 48px;
    }

    .input-group i {
        left: 16px;
        font-size: 1.1rem;
    }

    .verification-group .send-code-btn {
        padding: 14px 20px;
        border-radius: 10px;
        margin-left: 8px;
    }

    .checkbox-group {
        font-size: 0.9rem;
        margin-bottom: 2rem;
        line-height: 1.5;
    }

    .submit-btn {
        padding: 16px;
        font-size: 1.1rem;
        border-radius: 12px;
        margin-top: 0.5rem;
        margin-bottom: 1rem; /* 底部增加间距 */
    }
}

@media (max-width: 480px) {
    body {
        overflow-x: hidden;
        overflow-y: auto;
    }

    .main-header {
        padding: 1rem 4%;
        position: relative;
    }

    .logo {
        font-size: 1.8rem;
        margin-bottom: 0.8rem;
    }

    .logo i {
        font-size: 2rem;
    }

    .auth-nav {
        font-size: 0.9rem;
    }

    .auth-nav a {
        padding: 0.7rem 1.2rem;
        margin: 0 0.2rem;
        border-radius: 8px;
    }

    .main-content {
        padding: 1.5rem 4% 2rem; /* 进一步减少顶部间距 */
        gap: 2rem;
        min-height: auto;
        flex-grow: 0;
    }

    .intro-heading {
        font-size: 2rem;
        margin-bottom: 1rem;
    }

    .intro-subtext {
        font-size: 0.95rem;
        margin-bottom: 1.5rem;
    }

    .features-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
        margin-top: 1rem;
    }

    .feature-item {
        padding: 1rem 0.8rem;
        font-size: 0.85rem;
        border-radius: 8px;
    }

    .feature-item i {
        font-size: 1.8rem;
        margin-bottom: 0.6rem;
    }

    .form-card {
        padding: 2rem 1.5rem;
        border-radius: 15px;
        margin: 0 0 2rem 0;
    }

    .form-title {
        font-size: 1.6rem;
        margin-bottom: 1.8rem;
    }

    .input-group {
        margin-bottom: 1.2rem;
    }

    .input-group input {
        padding: 12px 12px 12px 42px;
        font-size: 0.95rem;
        border-radius: 8px;
    }

    .input-group i {
        left: 14px;
        font-size: 1rem;
    }

    .verification-group .send-code-btn {
        padding: 12px 16px;
        font-size: 0.9rem;
        border-radius: 8px;
        margin-left: 6px;
    }

    .checkbox-group {
        font-size: 0.85rem;
        margin-bottom: 1.8rem;
        line-height: 1.5;
    }

    .checkbox-group input[type="checkbox"] {
        width: 18px;
        height: 18px;
        margin-right: 10px;
    }

    .submit-btn {
        font-size: 1rem;
        padding: 14px;
        border-radius: 10px;
        margin-bottom: 1.5rem;
    }
}

/* 极小屏幕优化 (iPhone SE等) */
@media (max-width: 375px) {
    body {
        overflow-x: hidden;
        overflow-y: auto;
    }

    .main-header {
        padding: 0.8rem 3%;
        position: relative;
    }

    .logo {
        font-size: 1.6rem;
        margin-bottom: 0.6rem;
    }

    .logo i {
        font-size: 1.8rem;
        margin-right: 8px;
    }

    .auth-nav {
        font-size: 0.85rem;
    }

    .auth-nav a {
        padding: 0.6rem 1rem;
        margin: 0 0.1rem;
        border-radius: 6px;
    }

    .main-content {
        padding: 1rem 3% 2rem; /* 最小的顶部间距 */
        gap: 1.5rem;
        min-height: auto;
        flex-grow: 0;
    }

    .intro-heading {
        font-size: 1.8rem;
    }

    .intro-subtext {
        font-size: 0.9rem;
    }

    .feature-item {
        padding: 0.8rem;
        font-size: 0.8rem;
        border-radius: 6px;
    }

    .feature-item i {
        font-size: 1.6rem;
    }

    .form-card {
        padding: 1.8rem 1.2rem;
        border-radius: 12px;
        margin: 0 0 2rem 0;
    }

    .form-title {
        font-size: 1.4rem;
        margin-bottom: 1.5rem;
    }

    .input-group input {
        padding: 10px 10px 10px 38px;
        font-size: 0.9rem;
        border-radius: 6px;
    }

    .input-group i {
        left: 12px;
        font-size: 0.9rem;
    }

    .verification-group .send-code-btn {
        padding: 10px 14px;
        font-size: 0.85rem;
        border-radius: 6px;
        margin-left: 4px;
    }

    .checkbox-group {
        font-size: 0.8rem;
        margin-bottom: 1.5rem;
    }

    .checkbox-group input[type="checkbox"] {
        width: 16px;
        height: 16px;
        margin-right: 8px;
    }

    .submit-btn {
        font-size: 0.95rem;
        padding: 12px;
        border-radius: 8px;
        margin-bottom: 2rem; /* 增加底部间距 */
    }
}

/* 深色主题弹窗移动端优化 */
@media (max-width: 768px) {
    .layui-layer-dark-theme-modal {
        border-radius: 12px;
        margin: 20px;
        max-width: calc(100vw - 40px);
    }
    
    .layui-layer-dark-theme-modal .layui-layer-content {
        font-size: 15px;
        padding: 20px 18px;
        line-height: 1.6;
    }
}

@media (max-width: 480px) {
    .layui-layer-dark-theme-modal {
        border-radius: 10px;
        margin: 15px;
        max-width: calc(100vw - 30px);
    }
    
    .layui-layer-dark-theme-modal .layui-layer-content {
        font-size: 14px;
        padding: 18px 15px;
        line-height: 1.5;
    }

    .layui-layer-dark-theme-modal .layui-layer-ico {
        margin-top: 4px;
    }
}

@media (max-width: 375px) {
    .layui-layer-dark-theme-modal {
        border-radius: 8px;
        margin: 10px;
        max-width: calc(100vw - 20px);
    }
    
    .layui-layer-dark-theme-modal .layui-layer-content {
        font-size: 13px;
        padding: 15px 12px;
        line-height: 1.4;
    }
}

/* 深色主题弹窗样式 */
.layui-layer-dark-theme-modal {
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
    border: 1px solid #00d4ff;
    border-radius: 12px;
    box-shadow: 0 8px 32px rgba(0, 212, 255, 0.3);
}

.layui-layer-dark-theme-modal .layui-layer-content {
    color: #ffffff;
    background: transparent;
    font-family: 'Noto Sans SC', sans-serif;
    font-size: 16px;
    line-height: 1.6;
    text-align: center;
    padding: 20px;
}

.layui-layer-dark-theme-modal .layui-layer-ico1 {
    background-position: -48px -144px;
    filter: brightness(0) saturate(100%) invert(64%) sepia(95%) saturate(3064%) hue-rotate(167deg) brightness(101%) contrast(101%);
}

.layui-layer-dark-theme-modal .layui-layer-ico2 {
    background-position: -48px -240px;
    filter: brightness(0) saturate(100%) invert(48%) sepia(79%) saturate(2476%) hue-rotate(334deg) brightness(103%) contrast(97%);
}

.layui-layer-dark-theme-modal .layui-layer-ico {
    margin-top: 5px;
}

/* 弹窗动画效果 */
.layui-layer-dark-theme-modal {
    animation: modalFadeIn 0.3s ease-out;
}

@keyframes modalFadeIn {
    from {
        opacity: 0;
        transform: scale(0.8) translateY(-20px);
    }
    to {
        opacity: 1;
        transform: scale(1) translateY(0);
    }
}