/* ========= 全局设定 ========= */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --glass-bg: rgba(255, 255, 255, 0.45);
    --glass-border: rgba(255, 255, 255, 0.55);
    --glass-shadow: 0 30px 70px rgba(0,0,0,0.12), inset 0 0 0 1px rgba(255,255,255,0.8);
    --blue: #0071e3;
    --radius: 32px;
    --transition: 0.4s cubic-bezier(0.2, 0.9, 0.4, 1);
}

body {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", sans-serif;
    background: #eef2f5;
    position: relative;
    overflow-x: hidden;
}

/* ========= 动态流动背景 ========= */
body::before {
    content: "";
    position: fixed;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: 
        radial-gradient(circle at 20% 30%, rgba(0,113,227,0.1) 0%, transparent 40%),
        radial-gradient(circle at 80% 70%, rgba(100,210,255,0.1) 0%, transparent 40%),
        radial-gradient(circle at 50% 50%, rgba(255,255,255,0.3) 0%, transparent 60%);
    animation: bgFlow 20s linear infinite;
    z-index: 0;
    pointer-events: none;
}
@keyframes bgFlow {
    0% { transform: rotate(0deg) scale(1); }
    50% { transform: rotate(180deg) scale(1.1); }
    100% { transform: rotate(360deg) scale(1); }
}

/* ========= 主卡片 ========= */
.glass-card {
    position: relative;
    z-index: 1;
    background: var(--glass-bg);
    backdrop-filter: blur(40px) saturate(220%);
    -webkit-backdrop-filter: blur(40px) saturate(220%);
    border-radius: var(--radius);
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
    padding: 2.8rem 2.2rem;
    width: 95%;
    max-width: 480px;
    animation: cardFloat 8s ease-in-out infinite;
    transition: transform var(--transition);
    overflow: hidden;
}
.glass-card:hover {
    transform: translateY(-4px);
}

/* 浮动动画 */
@keyframes cardFloat {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-12px); }
}

/* 玻璃内部折射线（动态扫过） */
.glass-card::after {
    content: "";
    position: absolute;
    top: -50%;
    left: -60%;
    width: 50%;
    height: 200%;
    background: linear-gradient(
        120deg,
        transparent 20%,
        rgba(255,255,255,0.5) 40%,
        rgba(255,255,255,0.2) 50%,
        transparent 80%
    );
    transform: skewX(-25deg);
    animation: lightSweep 5s infinite;
    pointer-events: none;
}
@keyframes lightSweep {
    0% { left: -60%; }
    100% { left: 120%; }
}

/* 卡片内部光点 */
.glass-card::before {
    content: "";
    position: absolute;
    top: 15%;
    right: 10%;
    width: 120px;
    height: 120px;
    background: radial-gradient(circle, rgba(255,255,255,0.7) 0%, transparent 70%);
    border-radius: 50%;
    filter: blur(10px);
    animation: glowPulse 4s ease-in-out infinite alternate;
}
@keyframes glowPulse {
    0% { opacity: 0.3; transform: scale(0.9); }
    100% { opacity: 0.6; transform: scale(1.1); }
}

/* ========= 标题 ========= */
h1 {
    font-weight: 650;
    font-size: 2rem;
    color: #1d1d1f;
    text-align: center;
    margin-bottom: 1.8rem;
    letter-spacing: -0.5px;
    position: relative;
    z-index: 2;
}

/* ========= 输入框液态玻璃 ========= */
.input-field {
    background: rgba(255,255,255,0.55);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid rgba(0,0,0,0.06);
    border-radius: 18px;
    padding: 14px 18px;
    width: 100%;
    margin: 12px 0;
    font-size: 16px;
    outline: none;
    transition: all var(--transition);
    color: #1d1d1f;
    position: relative;
    z-index: 2;
}
.input-field:focus {
    border-color: var(--blue);
    box-shadow: 0 0 0 5px rgba(0,113,227,0.1), inset 0 0 10px rgba(255,255,255,0.5);
    background: rgba(255,255,255,0.8);
}

/* ========= 按钮 ========= */
.btn {
    background: var(--blue);
    color: white;
    border: none;
    border-radius: 22px;
    padding: 14px;
    width: 100%;
    font-weight: 600;
    font-size: 17px;
    margin-top: 18px;
    cursor: pointer;
    backdrop-filter: blur(10px);
    transition: all var(--transition);
    letter-spacing: 0.6px;
    position: relative;
    overflow: hidden;
    z-index: 2;
}
.btn::after {
    content: "";
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.3) 0%, transparent 60%);
    opacity: 0;
    transition: opacity 0.3s;
}
.btn:hover::after {
    opacity: 1;
}
.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 30px rgba(0,113,227,0.35);
}
.btn:active {
    transform: scale(0.97);
}

/* ========= 验证码 ========= */
.captcha-box {
    display: flex;
    align-items: center;
    gap: 12px;
    z-index: 2;
    position: relative;
}
.captcha-box img {
    height: 48px;
    border-radius: 14px;
    cursor: pointer;
    transition: transform 0.25s;
    border: 1px solid rgba(0,0,0,0.08);
    backdrop-filter: blur(10px);
}
.captcha-box img:hover {
    transform: scale(1.06);
}

/* 链接切换 */
.switch-link {
    text-align: center;
    margin-top: 24px;
    color: var(--blue);
    cursor: pointer;
    font-weight: 500;
    font-size: 15px;
    transition: opacity 0.2s;
    z-index: 2;
    position: relative;
}
.switch-link:hover {
    opacity: 0.7;
}

/* 语言选择器 */
.lang-select {
    position: fixed;
    top: 20px;
    right: 20px;
    background: rgba(255,255,255,0.55);
    backdrop-filter: blur(30px);
    -webkit-backdrop-filter: blur(30px);
    border-radius: 18px;
    padding: 6px 18px;
    border: 1px solid rgba(255,255,255,0.5);
    z-index: 999;
    box-shadow: 0 10px 25px rgba(0,0,0,0.05);
}
.lang-select select {
    background: transparent;
    border: none;
    font-size: 16px;
    font-weight: 500;
    outline: none;
    cursor: pointer;
}

/* 滚动条美化 */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
    background: rgba(0,0,0,0.15);
    border-radius: 12px;
    backdrop-filter: blur(5px);
}

/* SweetAlert2 液态玻璃定制（通过JS配置更好，这里做兜底） */
.swal2-popup {
    background: rgba(255,255,255,0.65) !important;
    backdrop-filter: blur(40px) saturate(200%) !important;
    -webkit-backdrop-filter: blur(40px) saturate(200%) !important;
    border-radius: 30px !important;
    border: 1px solid rgba(255,255,255,0.6) !important;
    box-shadow: 0 30px 60px rgba(0,0,0,0.15), inset 0 0 0 1px rgba(255,255,255,0.8) !important;
}