/* 🧠 뇌사료 | Premium Login Styles (v4.1) */

:root {
    --bg: #0b0f1a;
    --card: rgba(22, 30, 46, 0.6);
    --text: #f8fafc;
    --muted: #94a3b8;
    --accent: #38bdf8;
    --accent-hover: #0ea5e9;
    --ai-accent: #a855f7;
    --font: 'Inter', sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: var(--font); }

body {
    background-color: var(--bg);
    background-image: 
        radial-gradient(circle at 20% 30%, rgba(56, 189, 248, 0.1), transparent 40%),
        radial-gradient(circle at 80% 70%, rgba(168, 85, 247, 0.1), transparent 40%);
    color: var(--text);
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
}

.login-container {
    perspective: 1000px;
    width: 100%;
    max-width: 440px;
    padding: 20px;
}

.login-card {
    background: var(--card);
    backdrop-filter: blur(25px);
    -webkit-backdrop-filter: blur(25px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 32px;
    padding: 60px 45px;
    box-shadow: 0 50px 100px -20px rgba(0, 0, 0, 0.6);
    text-align: center;
    position: relative;
    overflow: hidden;
    animation: cardEntrance 0.8s cubic-bezier(0.2, 0.8, 0.2, 1);
}

@keyframes cardEntrance {
    from { opacity: 0; transform: translateY(40px) scale(0.95); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}

.login-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; width: 100%; height: 6px;
    background: linear-gradient(90deg, var(--accent), var(--ai-accent));
}

.logo-area {
    margin-bottom: 40px;
}

.logo {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 12px;
    background: linear-gradient(135deg, #38bdf8, #a855f7);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
}

.tagline {
    font-size: 0.95rem;
    color: var(--muted);
    font-weight: 400;
}

/* Form Styling */
.input-group {
    margin-bottom: 24px;
    text-align: left;
    position: relative;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-size: 0.85rem;
    color: var(--muted);
    font-weight: 600;
    margin-left: 4px;
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.input-wrapper input {
    width: 100%;
    background: rgba(0, 0, 0, 0.4);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 16px;
    padding: 16px 20px;
    color: white;
    outline: none;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    font-size: 1rem;
}

.input-wrapper input:focus {
    background: rgba(0, 0, 0, 0.6);
    border-color: var(--accent);
    box-shadow: 0 0 20px rgba(56, 189, 248, 0.1);
}

/* Button & Actions */
.login-btn {
    width: 100%;
    background: linear-gradient(135deg, var(--accent), #0ea5e9);
    color: #0f172a;
    border: none;
    border-radius: 16px;
    padding: 18px;
    font-size: 1.1rem;
    font-weight: 800;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 15px;
    box-shadow: 0 10px 25px -5px rgba(56, 189, 248, 0.4);
}

.login-btn:hover {
    transform: translateY(-3px);
    background: linear-gradient(135deg, #7dd3fc, var(--accent-hover));
    box-shadow: 0 15px 30px -5px rgba(56, 189, 248, 0.6);
}

.login-btn:active {
    transform: translateY(-1px);
}

.error-msg {
    color: #f87171;
    font-size: 0.85rem;
    margin-top: 20px;
    background: rgba(248, 113, 113, 0.1);
    padding: 10px;
    border-radius: 8px;
    display: none;
    animation: shake 0.4s;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

.login-card-footer {
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    font-size: 0.8rem;
    color: rgba(148, 163, 184, 0.5);
}