:root {
    --bg-color: #010204; /* Very deep blue-black */
    --glass-bg: rgba(10, 15, 25, 0.6);
    --glass-border: rgba(255, 255, 255, 0.1);
    --text-main: #ffffff;
    --text-dim: rgba(255, 255, 255, 0.6);
    --primary-glow: rgba(255, 60, 100, 0.5); /* A mix color glow for modal */
    --accent: #ff0055;
    --accent-hover: #00ffff;
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    font-family: 'Noto Sans SC', sans-serif;
    height: 100vh;
    overflow: hidden;
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
}

/* Canvas Background */
#bg-canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -1;
    background-color: #000;
}

/* Main Container */
.container {
    text-align: center;
    z-index: 10;
}

/* Premium Minimalist Cyber Button */
.cyber-btn {
    position: relative;
    padding: 18px 50px;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 100px; /* Pill shape for premium feel */
    cursor: pointer;
    outline: none;
    display: inline-flex;
    justify-content: center;
    align-items: center;
    backdrop-filter: blur(10px);
    transition: all 0.5s cubic-bezier(0.23, 1, 0.32, 1);
    overflow: hidden;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

.btn-text {
    font-size: 1.2rem;
    font-weight: 500;
    color: var(--text-main);
    z-index: 2;
    letter-spacing: 6px;
    transition: all 0.4s ease;
}

.cyber-btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 150%;
    height: 150%;
    background: conic-gradient(from 0deg, transparent 70%, rgba(255, 255, 255, 0.8) 80%, transparent 100%);
    transform: translate(-50%, -50%) rotate(0deg);
    animation: rotateGlow 4s linear infinite;
    z-index: 0;
    opacity: 0.3;
    pointer-events: none;
}

.cyber-btn::after {
    content: '';
    position: absolute;
    inset: 2px;
    background: rgba(5, 10, 15, 0.8);
    border-radius: 100px;
    z-index: 1;
    pointer-events: none;
}

@keyframes rotateGlow {
    0% { transform: translate(-50%, -50%) rotate(0deg); }
    100% { transform: translate(-50%, -50%) rotate(360deg); }
}

.cyber-btn:hover {
    border-color: rgba(255, 255, 255, 0.4);
    box-shadow: 0 0 40px rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.cyber-btn:hover .btn-text {
    text-shadow: 0 0 10px #ffffff;
    letter-spacing: 8px;
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
    opacity: 1;
    transition: opacity 0.5s ease, visibility 0.5s;
}

.modal.hidden {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
}

.modal-backdrop {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(20px);
}

/* Premium High-End Glass Panel */
.cyber-panel {
    position: relative;
    width: 380px;
    background: linear-gradient(135deg, rgba(255,255,255,0.05), rgba(255,255,255,0.01));
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 16px;
    padding: 32px 30px;
    z-index: 101;
    box-shadow: 0 30px 60px rgba(0, 0, 0, 0.6), inset 0 1px 0 rgba(255, 255, 255, 0.2);
    transform: scale(1) translateY(0);
    transition: transform 0.6s cubic-bezier(0.23, 1, 0.32, 1);
}

.modal.hidden .cyber-panel {
    transform: scale(0.95) translateY(20px);
}

.close-btn {
    position: absolute;
    top: 20px;
    right: 25px;
    background: none;
    border: none;
    color: var(--text-dim);
    font-size: 1.5rem;
    font-weight: 300;
    cursor: pointer;
    transition: all 0.3s;
}

.close-btn:hover {
    transform: rotate(90deg);
    color: #fff;
}

.modal-header {
    margin-bottom: 24px;
    text-align: center;
}

.modal-header h2 {
    font-size: 1.3rem;
    font-weight: 400;
    letter-spacing: 3px;
    color: #fff;
}

.modal-header p {
    font-size: 0.8rem;
    color: var(--text-dim);
    margin-top: 4px;
    letter-spacing: 2px;
}

/* Form Styles - Minimalist Input */
.input-group {
    position: relative;
    margin-bottom: 24px;
}

.input-group input {
    width: 100%;
    padding: 8px 0;
    background: transparent;
    border: none;
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
    outline: none;
    color: #fff;
    font-size: 1rem;
    letter-spacing: 1px;
    transition: border-color 0.3s;
}

.input-group label {
    position: absolute;
    top: 8px;
    left: 0;
    color: var(--text-dim);
    font-size: 0.85rem;
    pointer-events: none;
    transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    letter-spacing: 1px;
}

.input-group input:focus,
.input-group input:valid {
    border-bottom-color: #fff;
}

.input-group input:focus ~ label,
.input-group input:valid ~ label {
    top: -18px;
    font-size: 0.7rem;
    color: #fff;
}

/* Premium Submit Button */
.cyber-submit-btn {
    width: 100%;
    padding: 12px;
    background: #fff;
    border: none;
    border-radius: 100px;
    color: #000;
    font-size: 1rem;
    font-weight: 600;
    letter-spacing: 3px;
    cursor: pointer;
    transition: all 0.4s;
    margin-top: 12px;
}

.cyber-submit-btn:hover {
    background: transparent;
    color: #fff;
    box-shadow: inset 0 0 0 1px #fff;
    transform: translateY(-2px);
}

@media (max-width: 600px) {
    .cyber-panel { width: 90%; padding: 28px 20px; }
}

/* SMS验证码行 */
.sms-code-row {
    display: flex;
    gap: 10px;
    align-items: flex-end;
    margin-bottom: 24px;
}

.sms-btn {
    padding: 10px 16px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    color: #fff;
    font-size: 0.8rem;
    white-space: nowrap;
    cursor: pointer;
    transition: all 0.3s;
    flex-shrink: 0;
}

.sms-btn:hover {
    border-color: rgba(255, 255, 255, 0.5);
    background: rgba(255, 255, 255, 0.1);
}

.sms-btn.disabled {
    opacity: 0.4;
    pointer-events: none;
}

#login-error {
    color: #ff4444;
    font-size: 0.8rem;
    text-align: center;
    min-height: 20px;
    margin-bottom: 10px;
    transition: color 0.3s;
}

/* 管理员身份选择 */
.admin-choice-group {
    margin-bottom: 16px;
    padding: 10px 0;
}

.admin-checkbox-label {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    user-select: none;
}

.admin-checkbox-label input[type="checkbox"] {
    width: 16px;
    height: 16px;
    accent-color: var(--accent);
    cursor: pointer;
}

.admin-checkbox-text {
    color: var(--text-dim);
    font-size: 0.85rem;
    letter-spacing: 1px;
    transition: color 0.3s;
}

.admin-checkbox-label:hover .admin-checkbox-text {
    color: #fff;
}