:root {
    /* Premium Dark Palette */
    --bg-body: #0f172a;
    /* Deep Navy / Slate 900 */
    --bg-card: #1e293b;
    /* Slate 800 */
    --bg-card-hover: #334155;
    /* Slate 700 */

    --text-main: #f8fafc;
    /* Slate 50 */
    --text-muted: #94a3b8;
    /* Slate 400 */

    --primary: #f59e0b;
    /* Amber 500 - Transport/Warning Gold */
    --primary-hover: #d97706;
    /* Amber 600 */
    --primary-text: #0f172a;
    /* Dark text on gold button */

    --accent-blue: #3b82f6;
    /* Blue 500 - Secondary actions */

    --border: #334155;
    /* Slate 700 */
    --shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.5);

    --font-main: 'Inter', sans-serif;
    --radius: 12px;
}

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

body {
    background-color: var(--bg-body);
    color: var(--text-main);
    font-family: var(--font-main);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.2s;
}

ul {
    list-style: none;
}

/* Layout */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    width: 100%;
}

header {
    background-color: rgba(15, 23, 42, 0.9);
    /* Glass effect base */
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
    padding: 1rem 0;
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    color: var(--text-main);
}

.logo span {
    color: var(--primary);
}

nav ul {
    display: flex;
    gap: 2rem;
}

nav a {
    font-weight: 500;
    color: var(--text-muted);
}

nav a:hover,
nav a.active {
    color: var(--primary);
}

main {
    flex: 1;
    padding: 2rem 0;
}

/* Typography */
h1,
h2,
h3 {
    line-height: 1.2;
    margin-bottom: 1rem;
}

h1 {
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(to right, #fff, #94a3b8);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.lead {
    font-size: 1.25rem;
    color: var(--text-muted);
    max-width: 600px;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius);
    font-weight: 600;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s;
    border: none;
}

.btn-primary {
    background-color: var(--primary);
    color: var(--primary-text);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(245, 158, 11, 0.4);
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text-main);
}

.btn-outline:hover {
    border-color: var(--primary);
    color: var(--primary);
}

/* Cards */
.card {
    background-color: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2rem;
    transition: transform 0.2s, border-color 0.2s;
}

.card:hover {
    transform: translateY(-4px);
    border-color: var(--primary);
    box-shadow: var(--shadow);
}

/* Utilities */
.grid-auto-fit {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.grid-ads {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.flex-between {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .container {
        padding: 0 1rem;
    }

    /* Typography */
    h1 {
        font-size: 2rem;
    }

    /* Header & Navigation */
    header .container {
        flex-direction: column;
        gap: 1rem;
    }

    nav ul {
        gap: 1rem;
        flex-wrap: wrap;
        justify-content: center;
    }

    /* Cards & Grids */
    .grid-auto-fit,
    .grid-ads {
        grid-template-columns: 1fr;
        /* Stack on mobile */
        gap: 1rem;
    }

    .role-selection {
        grid-template-columns: 1fr !important;
    }

    /* Adjust form inputs */
    input,
    textarea {
        font-size: 16px;
        /* Prevent zoom on iOS */
    }

    .flex-between {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .flex-between .btn {
        width: 100%;
    }
}