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

:root {
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --background: #0f0f23;
    --card-bg: rgba(255, 255, 255, 0.95);
    --input-bg: #f8f9fa;
    --input-border: #e1e4e8;
    --text-primary: #24292e;
    --text-secondary: #586069;
    --error-color: #f85149;
    --success-color: #2ea043;
    --shadow: 0 8px 30px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.3);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--background);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    position: relative;
}

/* ========== ANIMATED BACKGROUND ========== */
#particles {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
}

/* ========== LOGIN CONTAINER ========== */
.login-container {
    position: relative;
    z-index: 10;
    width: 100%;
    max-width: 440px;
    padding: 20px;
    animation: fadeInUp 0.8s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ========== LOGIN CARD ========== */
.login-card {
    background: var(--card-bg);
    backdrop-filter: blur(10px);
    border-radius: 16px;
    padding: 48px 40px;
    box-shadow: var(--shadow-lg);
    border: 1px solid rgba(255, 255, 255, 0.2);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.login-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 25px 70px rgba(0, 0, 0, 0.4);
}

/* ========== LOGO ========== */
.logo {
    display: flex;
    justify-content: center;
    margin-bottom: 24px;
}

.logo svg {
    filter: drop-shadow(0 4px 12px rgba(102, 126, 234, 0.4));
}

/* ========== TITLES ========== */
.login-title {
    text-align: center;
    font-size: 32px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 8px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.login-subtitle {
    text-align: center;
    font-size: 15px;
    color: var(--text-secondary);
    margin-bottom: 32px;
}

/* ========== FORM ========== */
.login-form {
    width: 100%;
}

.form-group {
    margin-bottom: 24px;
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

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

.input-icon {
    position: absolute;
    left: 16px;
    color: var(--text-secondary);
    opacity: 0.6;
    pointer-events: none;
    z-index: 1;
}

.input-wrapper input {
    width: 100%;
    padding: 14px 16px 14px 48px;
    font-size: 15px;
    border: 2px solid var(--input-border);
    border-radius: 10px;
    background: var(--input-bg);
    color: var(--text-primary);
    transition: all 0.3s ease;
    outline: none;
}

.input-wrapper input:focus {
    border-color: var(--primary-color);
    background: #ffffff;
    box-shadow: 0 0 0 4px rgba(102, 126, 234, 0.1);
}

.input-wrapper input::placeholder {
    color: var(--text-secondary);
    opacity: 0.5;
}

/* ========== CHECKBOX ========== */
.form-options {
    margin-bottom: 24px;
}

.checkbox-wrapper {
    display: flex;
    align-items: center;
    cursor: pointer;
    user-select: none;
    position: relative;
    padding-left: 32px;
}

.checkbox-wrapper input[type="checkbox"] {
    position: absolute;
    opacity: 0;
    cursor: pointer;
}

.checkmark {
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    height: 20px;
    width: 20px;
    background-color: var(--input-bg);
    border: 2px solid var(--input-border);
    border-radius: 6px;
    transition: all 0.3s ease;
}

.checkbox-wrapper:hover .checkmark {
    border-color: var(--primary-color);
}

.checkbox-wrapper input:checked ~ .checkmark {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-color: var(--primary-color);
}

.checkmark:after {
    content: "";
    position: absolute;
    display: none;
    left: 6px;
    top: 2px;
    width: 5px;
    height: 10px;
    border: solid white;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.checkbox-wrapper input:checked ~ .checkmark:after {
    display: block;
}

.checkbox-label {
    font-size: 14px;
    color: var(--text-secondary);
}

/* ========== BUTTON ========== */
.btn-login {
    width: 100%;
    padding: 16px;
    font-size: 16px;
    font-weight: 600;
    color: white;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.btn-login:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.6);
}

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

.btn-login.loading {
    pointer-events: none;
}

.btn-text {
    display: inline-block;
    transition: opacity 0.3s ease;
}

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

.btn-loader {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.btn-login.loading .btn-loader {
    opacity: 1;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to {
        transform: translate(-50%, -50%) rotate(360deg);
    }
}

/* ========== ERROR MESSAGE ========== */
.error-message {
    margin-top: 16px;
    padding: 12px 16px;
    background: rgba(248, 81, 73, 0.1);
    border: 1px solid var(--error-color);
    border-radius: 8px;
    color: var(--error-color);
    font-size: 14px;
    display: none;
    animation: shake 0.4s ease;
}

.error-message.show {
    display: block;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-10px); }
    75% { transform: translateX(10px); }
}

/* ========== FOOTER ========== */
.footer {
    text-align: center;
    margin-top: 24px;
    padding-top: 20px;
}

.footer p {
    font-size: 13px;
    color: rgba(255, 255, 255, 0.6);
}

/* ========== RESPONSIVE ========== */
@media (max-width: 480px) {
    .login-container {
        padding: 16px;
    }

    .login-card {
        padding: 32px 24px;
    }

    .login-title {
        font-size: 28px;
    }
}