:root {
    --primary: #00f2ff;
    --primary-glow: rgba(0, 242, 255, 0.15);
    --bg: #030303;
    --surface: #0a0a0a;
    --border: #1a1a1a;
    --text: #fff;
    --text-dim: #666;
    --error: #f44;
    --ease: cubic-bezier(0.2, 0, 0, 1);
}

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

body {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg);
    font-family: 'Inter', -apple-system, sans-serif;
    color: var(--text);
    -webkit-font-smoothing: antialiased;
    overflow: hidden;
    transition: opacity 0.6s var(--ease);
}

.login-card {
    width: 100%;
    max-width: 360px;
    padding: 48px 40px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 16px;
    animation: cardEntrance 0.8s var(--ease);
}

@keyframes cardEntrance {
    from { opacity: 0; transform: scale(0.98) translateY(10px); }
}

.header { 
    text-align: center; 
    margin-bottom: 40px; 
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 900;
    letter-spacing: 3px;
}

.logo-accent {
    color: var(--primary);
    text-shadow: 0 0 20px var(--primary-glow);
}

.tagline { 
    font-size: 0.6rem; 
    color: var(--text-dim); 
    text-transform: uppercase; 
    letter-spacing: 3px; 
}

.input-group { 
    margin-bottom: 28px; 
}

.input-group label {
    display: block;
    font-size: 0.65rem;
    font-weight: 700;
    color: var(--text-dim);
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 1.5px;
}

input {
    width: 100%;
    padding: 14px 18px;
    background: #0d0d0d;
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text);
    font-size: 0.9rem;
    outline: none;
    transition: all 0.3s var(--ease);
}

input:focus { 
    border-color: var(--primary); 
    background: #111; 
}

.btn-submit {
    position: relative;
    width: 100%;
    padding: 16px;
    background: #fff;
    border: none;
    border-radius: 8px;
    color: #000;
    font-size: 0.85rem;
    font-weight: 800;
    letter-spacing: 1px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s var(--ease);
}

.btn-submit:hover { 
    background: var(--primary); 
}

.btn-submit:active {
    transform: scale(0.97);
}

.btn-text, .spinner {
    transition: opacity 0.3s var(--ease);
}

.spinner {
    position: absolute;
    width: 18px;
    height: 18px;
    border: 2px solid rgba(0,0,0,0.1);
    border-top-color: #000;
    border-radius: 50%;
    opacity: 0;
}

.btn-submit.loading .btn-text {
    opacity: 0;
}

.btn-submit.loading .spinner {
    opacity: 1;
    animation: spin 0.6s linear infinite;
}

@keyframes spin { 
    to { transform: rotate(360deg); } 
}

.error-container {
    height: 20px;
    margin-top: 15px;
}

.error-box {
    width: 100%;
    color: var(--error);
    font-size: 0.7rem;
    text-align: center;
    opacity: 0;
    transition: all 0.3s var(--ease);
}

.error-box.visible {
    opacity: 1;
    transform: translateY(0);
}

.footer { 
    margin-top: 25px; 
    text-align: center; 
    font-size: 0.55rem; 
    color: var(--text-dim); 
    letter-spacing: 2px; 
    text-transform: uppercase; 
    opacity: 0.5; 
}