/* === Base Reset === */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #3b82f6;
    --primary-gradient: linear-gradient(135deg, #60a5fa 0%, #3b82f6 100%);
    --bg-light: linear-gradient(135deg, #dfe9f3 0%, #ffffff 100%);
    --bg-dark: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    --text-color: #1e3a8a;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --error-color: #ef4444;
}

/* === Light Mode (Default) === */
body {
    font-family: 'Inter', sans-serif;
    background: var(--bg-light);
    color: var(--text-color);
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100vh;
    transition: background 0.4s ease, color 0.3s ease;
}

.container {
    background: rgba(255, 255, 255, 0.9);
    border-radius: 24px;
    padding: 50px 40px;
    max-width: 400px;
    width: 100%;
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.08);
    text-align: center;
    backdrop-filter: blur(10px);
    transition: all 0.3s ease;
}

.container:hover {
    transform: translateY(-3px);
}

.logo {
    display: block;
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 10px;
}

h1 {
    font-size: 1.8rem;
    margin-bottom: 10px;
    font-weight: 600;
}

.subtitle {
    font-size: 0.95rem;
    color: var(--text-muted);
    margin-bottom: 25px;
}

/* === Form Styling === */
.form-group {
    position: relative;
    margin-bottom: 20px;
    text-align: left;
}

label {
    display: block;
    margin-bottom: 6px;
    font-weight: 500;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.input-icon {
    position: absolute;
    left: 15px;
    top: 50%;
    transform: translateY(5px);
    color: #94a3b8;
    font-size: 0.95rem;
}

input {
    width: 100%;
    padding: 12px 40px 12px 40px;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    font-size: 15px;
    background-color: #f8fafc;
    transition: all 0.3s ease;
}

input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

/* === Button === */
button[type="submit"] {
    width: 100%;
    padding: 14px;
    background: var(--primary-gradient);
    color: white;
    font-size: 1rem;
    border: none;
    border-radius: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: 0.3s ease;
}

button[type="submit"]:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(59, 130, 246, 0.3);
}

button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

/* === Loading Spinner === */
.loading {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 3px solid #ffffff80;
    border-top-color: #fff;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-right: 8px;
}

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

/* === Error Message === */
#errorMsg {
    margin-top: 10px;
    font-size: 0.9rem;
    color: var(--error-color);
    min-height: 20px;
    transition: opacity 0.4s ease;
}

/* === Links === */
.links {
    margin-top: 20px;
    display: flex;
    justify-content: space-between;
    font-size: 0.9rem;
}

.links a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s;
}

.links a:hover {
    text-decoration: underline;
}

/* === Theme Toggle === */
.theme-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 50%;
    width: 42px;
    height: 42px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: 0.3s;
}

.theme-toggle:hover {
    background: #2563eb;
}

.theme-toggle i {
    font-size: 1.1rem;
}

/* === Dark Mode === */
[data-theme="dark"] {
    background: var(--bg-dark);
    color: #e2e8f0;
}

[data-theme="dark"] .container {
    background: #1e293b;
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.6);
}

[data-theme="dark"] .logo {
    color: #93c5fd;
}

[data-theme="dark"] h1 {
    color: #f1f5f9;
}

[data-theme="dark"] .subtitle {
    color: #94a3b8;
}

[data-theme="dark"] input {
    background-color: #334155;
    border-color: #475569;
    color: #f1f5f9;
}

[data-theme="dark"] input:focus {
    border-color: #60a5fa;
    box-shadow: 0 0 0 3px rgba(96, 165, 250, 0.3);
}

[data-theme="dark"] button[type="submit"] {
    background: linear-gradient(135deg, #2563eb 0%, #1e40af 100%);
}

[data-theme="dark"] .theme-toggle {
    background: #475569;
    color: #f1f5f9;
}

[data-theme="dark"] .links a {
    color: #93c5fd;
}

/* === Responsive === */
@media (max-width: 480px) {
    .container {
        padding: 35px 25px;
    }

    .links {
        flex-direction: column;
        gap: 10px;
    }
}