:root {
    --color-primary: #667eea;
    --color-primary-dark: #764ba2;
    --color-text: #1a1a1a;
    --color-text-muted: #6b7280;
    --color-border: #e5e7eb;
    --color-bg-card: rgba(255, 255, 255, 0.95);
    --color-error: #c62828;
    --color-error-bg: #fff5f5;
    --color-success: #2e7d32;
    --color-success-bg: #f0fdf4;
    --color-info: #1e40af;
    --color-info-bg: #eff6ff;
    --radius-card: 20px;
    --radius-input: 12px;
    --shadow-card: 0 20px 60px rgba(0, 0, 0, 0.3);
    --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

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

html {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    color: var(--color-text);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    background-attachment: fixed;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 24px;
    position: relative;
    overflow-x: hidden;
}

body::before,
body::after {
    content: "";
    position: absolute;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.08);
    animation: float 6s ease-in-out infinite;
    pointer-events: none;
}

body::before { width: 300px; height: 300px; top: -150px; left: -150px; }
body::after  { width: 400px; height: 400px; bottom: -200px; right: -200px; animation-delay: 2s; }

@keyframes float {
    0%, 100% { transform: translateY(0) scale(1); }
    50%      { transform: translateY(-30px) scale(1.05); }
}

.container {
    width: 100%;
    max-width: 460px;
    position: relative;
    z-index: 1;
}

.brand {
    text-align: center;
    margin-bottom: 28px;
}

.brand-title {
    font-size: 28px;
    font-weight: 800;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.brand-subtitle {
    color: var(--color-text-muted);
    font-size: 14px;
    margin-top: 4px;
}

.btn {
    width: 100%;
    padding: 14px 24px;
    border: none;
    border-radius: var(--radius-input);
    font: inherit;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease, opacity 0.2s ease;
    letter-spacing: 0.3px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: white;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.35);
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 25px rgba(102, 126, 234, 0.45);
}

.btn-primary:active { transform: translateY(0); }

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.error-message,
.success-message,
.info-message {
    margin-top: 18px;
    padding: 12px 14px;
    border-radius: var(--radius-input);
    font-size: 14px;
    font-weight: 500;
    display: none;
    animation: slideDown 0.25s ease-out;
    border-left: 4px solid currentColor;
}

.error-message    { color: var(--color-error);   background: var(--color-error-bg); }
.success-message  { color: var(--color-success); background: var(--color-success-bg); }
.info-message     { color: var(--color-info);    background: var(--color-info-bg); }

.error-message.show,
.success-message.show,
.info-message.show { display: block; }

@keyframes slideDown {
    from { opacity: 0; transform: translateY(-6px); }
    to   { opacity: 1; transform: translateY(0); }
}

@media (max-width: 600px) {
    body::before, body::after { display: none; }
}