/* Apple-inspired Design System */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600&display=swap');

:root {
    /* Light Mode (Default) */
    --bg-primary: #f5f5f7;
    --bg-secondary: #ffffff;
    --text-primary: #1d1d1f;
    --text-secondary: #86868b;
    --accent: #0071e3;
    --accent-hover: #0077ed;
    --border: #d2d2d7;
    --card-bg: rgba(255, 255, 255, 0.8);
    --input-bg: rgba(255, 255, 255, 0.8);
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
    --glass-border: 1px solid rgba(255, 255, 255, 0.4);
    --danger: #ff3b30;
    --success: #34c759;
}

[data-theme="dark"] {
    --bg-primary: #000000;
    --bg-secondary: #1c1c1e;
    --text-primary: #f5f5f7;
    --text-secondary: #86868b;
    --accent: #2997ff;
    --accent-hover: #409cff;
    --border: #38383a;
    --card-bg: rgba(28, 28, 30, 0.8);
    --input-bg: rgba(28, 28, 30, 0.6);
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
    --glass-border: 1px solid rgba(255, 255, 255, 0.1);
}

* { box-sizing: border-box; transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease; }

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    margin: 0;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3 { font-weight: 600; letter-spacing: -0.015em; }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Components */
.card {
    background: var(--card-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 18px;
    padding: 2rem;
    box-shadow: var(--shadow);
    border: var(--glass-border);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.8rem 1.5rem;
    border-radius: 980px; /* Pill shape */
    font-weight: 500;
    font-size: 0.95rem;
    cursor: pointer;
    border: none;
    transition: all 0.2s ease;
    background: var(--accent);
    color: #fff;
}
.btn:hover { background: var(--accent-hover); transform: scale(1.02); }
.btn:active { transform: scale(0.98); }

.btn-secondary { background: var(--bg-secondary); color: var(--text-primary); border: 1px solid var(--border); }
.btn-secondary:hover { background: var(--border); }

.btn-danger { background: transparent; color: var(--danger); }
.btn-danger:hover { background: rgba(255, 59, 48, 0.1); }

input[type="text"], input[type="password"], textarea {
    width: 100%;
    padding: 1rem;
    border-radius: 12px;
    border: 1px solid var(--border);
    background: var(--input-bg);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
    outline: none;
}
input:focus, textarea:focus { border-color: var(--accent); box-shadow: 0 0 0 4px rgba(41, 151, 255, 0.15); }

/* Layout Helpers */
.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 2rem;
}

.flex-center { display: flex; justify-content: center; align-items: center; min-height: 100vh; }
.flex-between { display: flex; justify-content: space-between; align-items: center; }

/* Theme Toggle */
.theme-toggle {
    background: none;
    border: none;
    color: var(--text-primary);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    font-size: 1.2rem;
}
.theme-toggle:hover { background: rgba(128,128,128,0.1); }

/* Loaders */
.loader {
    width: 1rem; height: 1rem; border: 2px solid var(--text-secondary);
    border-top-color: var(--accent); border-radius: 50%;
    animation: spin 1s linear infinite; display: inline-block;
}
@keyframes spin { to { transform: rotate(360deg); } }