:root {
    --thv-color-bg: #ffffff;
    --thv-color-bg-alt: #f3f6fc;
    --thv-color-accent: #1d4ed8;
    --thv-color-accent-dark: #1e3a8a;
    --thv-color-accent-light: #3b82f6;
    --thv-color-text: #111827;
    --thv-color-text-muted: #4b5563;
    --thv-color-border: #dde3ee;
    --thv-radius: 12px;
    --thv-radius-sm: 8px;
    --thv-shadow: 0 2px 14px rgba(15, 23, 42, 0.08);
    --thv-shadow-lg: 0 12px 32px rgba(15, 23, 42, 0.16);
    --thv-header-height: 64px;
}

* {
    box-sizing: border-box;
}

html, body {
    height: 100%;
}

body {
    margin: 0;
    font-family: "Segoe UI", Roboto, -apple-system, BlinkMacSystemFont, sans-serif;
    color: var(--thv-color-text);
    background: var(--thv-color-bg);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

h1, h2, h3 {
    line-height: 1.25;
    margin: 0 0 0.5em;
}

p {
    line-height: 1.6;
    color: var(--thv-color-text-muted);
}

a {
    color: var(--thv-color-accent);
}

img {
    max-width: 100%;
    display: block;
}

/* Header */
.thv-header {
    height: var(--thv-header-height);
    border-bottom: 1px solid var(--thv-color-border);
    background: var(--thv-color-bg);
    position: sticky;
    top: 0;
    z-index: 50;
}

.thv-header__inner {
    max-width: 1200px;
    margin: 0 auto;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 20px;
}

.thv-header__brand {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: var(--thv-color-text);
}

.thv-header__logo {
    height: 40px;
    width: auto;
    display: block;
}

.thv-header__nav a {
    text-decoration: none;
    color: var(--thv-color-text);
    font-weight: 500;
    padding: 8px 12px;
    border-radius: var(--thv-radius-sm);
}

.thv-header__nav a:hover,
.thv-header__nav a:focus-visible {
    background: var(--thv-color-bg-alt);
    color: var(--thv-color-accent-dark);
}

.thv-main {
    flex: 1;
}

.thv-footer {
    border-top: 1px solid var(--thv-color-border);
    padding: 20px;
    text-align: center;
    color: var(--thv-color-text-muted);
    font-size: 0.85rem;
}

/* Buttons */
.thv-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: var(--thv-radius-sm);
    font-weight: 600;
    font-size: 0.95rem;
    text-decoration: none;
    border: 1px solid transparent;
    cursor: pointer;
    transition: background-color 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.thv-btn--primary {
    background: var(--thv-color-accent);
    color: #fff;
}

.thv-btn--primary:hover,
.thv-btn--primary:focus-visible {
    background: var(--thv-color-accent-dark);
    color: #fff;
}

.thv-btn--ghost {
    background: var(--thv-color-bg);
    color: var(--thv-color-text);
    border-color: var(--thv-color-border);
}

.thv-btn--ghost:hover,
.thv-btn--ghost:focus-visible {
    border-color: var(--thv-color-accent);
    color: var(--thv-color-accent-dark);
}

.thv-btn:focus-visible {
    outline: 2px solid var(--thv-color-accent);
    outline-offset: 2px;
}

.thv-empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--thv-color-text-muted);
}

.thv-error-page {
    max-width: 560px;
    margin: 80px auto;
    text-align: center;
    padding: 0 20px;
}

.thv-error-page h1 {
    font-size: 4rem;
    color: var(--thv-color-accent);
    margin-bottom: 0.2em;
}